Don't try to use to_underlying for non-enum C++ types.

[bzbarsky-apple]

Fixes project-chip/zap#591

Problem

Using the wrong predicate to determine "this is a C++ enum type"

Change overview

Use the right predicate.

Testing

Checked that codegen does not change after updating to ZAP tip.

[github-actions]

PR #20554: Size comparison from 0ca7902 to 11ee7e5

Increases (3 builds for cc13x2_26x2, cyw30739)

platform	target	config	section	0ca7902	11ee7e5	change	% change
cc13x2_26x2	pump-controller-app	LP_CC2652R7	(read/write)	178520	178528	8	0.0
	shell	LP_CC2652R7	(read/write)	188176	188184	8	0.0
cyw30739	ota-requestor-no-progress-logging	cyw930739m2evb_01	(read/write)	582598	582606	8	0.0
			.app_xip_area	462200	462208	8	0.0

Decreases (3 builds for cc13x2_26x2, esp32)

platform	target	config	section	0ca7902	11ee7e5	change	% change
cc13x2_26x2	pump-controller-app	LP_CC2652R7	(read only)	663815	663807	-8	-0.0
			.text	579040	579032	-8	-0.0
	shell	LP_CC2652R7	(read only)	658550	658542	-8	-0.0
			.text	573388	573380	-8	-0.0
esp32	all-clusters-app	c3devkit	(read only)	1019994	1019992	-2	-0.0
			.flash.text	1019994	1019992	-2	-0.0

Full report (41 builds for cc13x2_26x2, cyw30739, efr32, esp32, k32w, linux, mbed, nrfconnect, p6, telink)

platform	target	config	section	0ca7902	11ee7e5	change	% change
cc13x2_26x2	all-clusters-app	LP_CC2652R7	(read only)	666051	666051	0	0.0
			(read/write)	185172	185172	0	0.0
			.bss	74116	74116	0	0.0
			.data	3356	3356	0	0.0
			.rodata	88067	88067	0	0.0
			.text	577668	577668	0	0.0
	all-clusters-minimal-app	LP_CC2652R7	(read only)	631859	631859	0	0.0
			(read/write)	157684	157684	0	0.0
			.bss	73412	73412	0	0.0
			.data	3356	3356	0	0.0
			.rodata	77307	77307	0	0.0
			.text	554228	554228	0	0.0
	lock-ftd	LP_CC2652R7	(read only)	668959	668959	0	0.0
			(read/write)	172408	172408	0	0.0
			.bss	71148	71148	0	0.0
			.data	3280	3280	0	0.0
			.rodata	76207	76207	0	0.0
			.text	592272	592272	0	0.0
	lock-mtd	LP_CC2652R7	(read only)	618367	618367	0	0.0
			(read/write)	144264	144264	0	0.0
			.bss	66868	66868	0	0.0
			.data	3280	3280	0	0.0
			.rodata	76087	76087	0	0.0
			.text	541792	541792	0	0.0
	pump-app	LP_CC2652R7	(read only)	677991	677991	0	0.0
			(read/write)	164224	164224	0	0.0
			.bss	71228	71228	0	0.0
			.data	3280	3280	0	0.0
			.rodata	88431	88431	0	0.0
			.text	589076	589076	0	0.0
	pump-controller-app	LP_CC2652R7	(read only)	663815	663807	-8	-0.0
			(read/write)	178520	178528	8	0.0
			.bss	71348	71348	0	0.0
			.data	3276	3276	0	0.0
			.rodata	84295	84295	0	0.0
			.text	579040	579032	-8	-0.0
	shell	LP_CC2652R7	(read only)	658550	658542	-8	-0.0
			(read/write)	188176	188184	8	0.0
			.bss	76420	76420	0	0.0
			.data	3360	3360	0	0.0
			.rodata	84846	84846	0	0.0
			.text	573388	573380	-8	-0.0
cyw30739	light	cyw930739m2evb_01	(read/write)	579550	579550	0	0.0
			.app_xip_area	458304	458304	0	0.0
			.bss	64184	64184	0	0.0
			.data	716	716	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
	lock	cyw930739m2evb_01	(read/write)	585478	585478	0	0.0
			.app_xip_area	459504	459504	0	0.0
			.bss	68912	68912	0	0.0
			.data	720	720	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
	ota-requestor-no-progress-logging	cyw930739m2evb_01	(read/write)	582598	582606	8	0.0
			.app_xip_area	462200	462208	8	0.0
			.bss	63392	63392	0	0.0
			.data	660	660	0	0.0
			.rodata	0	0	0	0.0
			.text	112	112	0	0.0
efr32	lighting-app	BRD4161A	(read/write)	1081316	1081316	0	0.0
			.bss	132996	132996	0	0.0
			.data	2048	2048	0	0.0
			.text	946252	946252	0	0.0
		BRD4161A+rpc	(read/write)	1135644	1135644	0	0.0
			.bss	149676	149676	0	0.0
			.data	2260	2260	0	0.0
			.text	983688	983688	0	0.0
		BRD4161A+rs911x	(read/write)	947804	947804	0	0.0
			.bss	140768	140768	0	0.0
			.data	2048	2048	0	0.0
			.text	804968	804968	0	0.0
	lock-app	BRD4161A+wf200	(read/write)	1128616	1128616	0	0.0
			.bss	144184	144184	0	0.0
			.data	2060	2060	0	0.0
			.text	982348	982348	0	0.0
	window-app	BRD4161A	(read/write)	1075108	1075108	0	0.0
			.bss	134468	134468	0	0.0
			.data	2076	2076	0	0.0
			.text	938540	938540	0	0.0
esp32	all-clusters-app	c3devkit	(read only)	1019994	1019992	-2	-0.0
			(read/write)	1485570	1485570	0	0.0
			.dram0.bss	70080	70080	0	0.0
			.dram0.data	14600	14600	0	0.0
			.flash.rodata	215456	215456	0	0.0
			.flash.text	1019994	1019992	-2	-0.0
			.iram0.text	62902	62902	0	0.0
		m5stack	(read only)	1073943	1073943	0	0.0
			(read/write)	487648	487648	0	0.0
			.dram0.bss	75600	75600	0	0.0
			.dram0.data	34144	34144	0	0.0
			.flash.rodata	245908	245908	0	0.0
			.flash.text	1068559	1068559	0	0.0
			.iram0.text	123267	123267	0	0.0
k32w	light	k32w061+release	(read/write)	658704	658704	0	0.0
			.bss	69516	69516	0	0.0
			.data	1992	1992	0	0.0
			.text	581396	581396	0	0.0
	lock	k32w061+release	(read/write)	685468	685468	0	0.0
			.bss	69980	69980	0	0.0
			.data	2004	2004	0	0.0
			.text	607684	607684	0	0.0
linux	all-clusters-app	debug	(read only)	2960481	2960481	0	0.0
			(read/write)	154744	154744	0	0.0
			.bss	61536	61536	0	0.0
			.data	2048	2048	0	0.0
			.data.rel.ro	84968	84968	0	0.0
			.dynamic	608	608	0	0.0
			.got	4536	4536	0	0.0
			.init	27	27	0	0.0
			.init_array	1040	1040	0	0.0
			.rodata	263549	263549	0	0.0
			.text	2519746	2519746	0	0.0
	all-clusters-minimal-app	debug	(read only)	2813025	2813025	0	0.0
			(read/write)	146680	146680	0	0.0
			.bss	60864	60864	0	0.0
			.data	2048	2048	0	0.0
			.data.rel.ro	77608	77608	0	0.0
			.dynamic	608	608	0	0.0
			.got	4488	4488	0	0.0
			.init	27	27	0	0.0
			.init_array	1040	1040	0	0.0
			.rodata	265245	265245	0	0.0
			.text	2372770	2372770	0	0.0
	bridge-app	debug+rpc	(read only)	2315225	2315225	0	0.0
			(read/write)	125504	125504	0	0.0
			.bss	48928	48928	0	0.0
			.data	3824	3824	0	0.0
			.data.rel.ro	66984	66984	0	0.0
			.dynamic	608	608	0	0.0
			.got	4392	4392	0	0.0
			.init	27	27	0	0.0
			.init_array	728	728	0	0.0
			.rodata	197952	197952	0	0.0
			.text	1955538	1955538	0	0.0
	chip-tool	debug	(read only)	10316465	10316465	0	0.0
			(read/write)	622240	622240	0	0.0
			.bss	24728	24728	0	0.0
			.data	3234	3234	0	0.0
			.data.rel.ro	587888	587888	0	0.0
			.dynamic	608	608	0	0.0
			.got	5096	5096	0	0.0
			.init	27	27	0	0.0
			.init_array	640	640	0	0.0
			.rodata	514933	514933	0	0.0
			.text	8369844	8369844	0	0.0
	chip-tool-no-interactive-ipv6only	arm64	(read only)	10008404	10008404	0	0.0
			(read/write)	684529	684529	0	0.0
			.bss	42609	42609	0	0.0
			.data	1152	1152	0	0.0
			.data.rel.ro	623432	623432	0	0.0
			.dynamic	528	528	0	0.0
			.got	13520	13520	0	0.0
			.init	24	24	0	0.0
			.init_array	192	192	0	0.0
			.rodata	477652	477652	0	0.0
			.text	7970084	7970084	0	0.0
	lighting-app	debug+rpc	(read only)	2550969	2550969	0	0.0
			(read/write)	129528	129528	0	0.0
			.bss	49440	49440	0	0.0
			.data	2096	2096	0	0.0
			.data.rel.ro	72136	72136	0	0.0
			.dynamic	608	608	0	0.0
			.got	4392	4392	0	0.0
			.init	27	27	0	0.0
			.init_array	816	816	0	0.0
			.rodata	213640	213640	0	0.0
			.text	2167362	2167362	0	0.0
	lock-app	debug	(read only)	2515569	2515569	0	0.0
			(read/write)	124504	124504	0	0.0
			.bss	47840	47840	0	0.0
			.data	1712	1712	0	0.0
			.data.rel.ro	69096	69096	0	0.0
			.dynamic	608	608	0	0.0
			.got	4424	4424	0	0.0
			.init	27	27	0	0.0
			.init_array	784	784	0	0.0
			.rodata	228680	228680	0	0.0
			.text	2121746	2121746	0	0.0
	ota-provider-app	debug	(read only)	2322049	2322049	0	0.0
			(read/write)	118312	118312	0	0.0
			.bss	47488	47488	0	0.0
			.data	1944	1944	0	0.0
			.data.rel.ro	63096	63096	0	0.0
			.dynamic	608	608	0	0.0
			.got	4488	4488	0	0.0
			.init	27	27	0	0.0
			.init_array	672	672	0	0.0
			.rodata	203416	203416	0	0.0
			.text	1955858	1955858	0	0.0
	ota-requestor-app	debug	(read only)	2439169	2439169	0	0.0
			(read/write)	125216	125216	0	0.0
			.bss	49856	49856	0	0.0
			.data	2232	2232	0	0.0
			.data.rel.ro	67288	67288	0	0.0
			.dynamic	608	608	0	0.0
			.got	4480	4480	0	0.0
			.init	27	27	0	0.0
			.init_array	728	728	0	0.0
			.rodata	207200	207200	0	0.0
			.text	2060818	2060818	0	0.0
	shell	debug	(read only)	2550825	2550825	0	0.0
			(read/write)	141096	141096	0	0.0
			.bss	57448	57448	0	0.0
			.data	1264	1264	0	0.0
			.data.rel.ro	76688	76688	0	0.0
			.dynamic	608	608	0	0.0
			.got	4136	4136	0	0.0
			.init	27	27	0	0.0
			.init_array	920	920	0	0.0
			.rodata	227698	227698	0	0.0
			.text	2166050	2166050	0	0.0
	thermostat-no-ble	arm64	(read only)	2595076	2595076	0	0.0
			(read/write)	158289	158289	0	0.0
			.bss	65249	65249	0	0.0
			.data	1704	1704	0	0.0
			.data.rel.ro	83240	83240	0	0.0
			.dynamic	528	528	0	0.0
			.got	5072	5072	0	0.0
			.init	24	24	0	0.0
			.init_array	400	400	0	0.0
			.rodata	165412	165412	0	0.0
			.text	2189888	2189888	0	0.0
	tv-app	debug	(read only)	3101969	3101969	0	0.0
			(read/write)	257704	257704	0	0.0
			.bss	167016	167016	0	0.0
			.data	4848	4848	0	0.0
			.data.rel.ro	79392	79392	0	0.0
			.dynamic	608	608	0	0.0
			.got	4848	4848	0	0.0
			.init	27	27	0	0.0
			.init_array	952	952	0	0.0
			.rodata	248928	248928	0	0.0
			.text	2665138	2665138	0	0.0
	tv-casting-app	debug	(read only)	5577561	5577561	0	0.0
			(read/write)	161968	161968	0	0.0
			.bss	50248	50248	0	0.0
			.data	2416	2416	0	0.0
			.data.rel.ro	103048	103048	0	0.0
			.dynamic	608	608	0	0.0
			.got	4744	4744	0	0.0
			.init	27	27	0	0.0
			.init_array	864	864	0	0.0
			.rodata	343145	343145	0	0.0
			.text	4956466	4956466	0	0.0
mbed	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2447912	2447912	0	0.0
			.bss	213940	213940	0	0.0
			.data	5872	5872	0	0.0
			.text	1410556	1410556	0	0.0
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read/write)	1174935	1174935	0	0.0
			bss	142900	142900	0	0.0
			rodata	141808	141808	0	0.0
			text	811332	811332	0	0.0
	all-clusters-minimal-app	nrf52840dk_nrf52840	(read/write)	1155131	1155131	0	0.0
			bss	142136	142136	0	0.0
			rodata	133340	133340	0	0.0
			text	800776	800776	0	0.0
p6	all-clusters-app	default	(read/write)	2565256	2565256	0	0.0
			.bss	149120	149120	0	0.0
			.data	2776	2776	0	0.0
			.text	1523520	1523520	0	0.0
	all-clusters-minimal-app	default	(read/write)	2510320	2510320	0	0.0
			.bss	148400	148400	0	0.0
			.data	2776	2776	0	0.0
			.text	1468584	1468584	0	0.0
	light-app	default	(read/write)	2440600	2440600	0	0.0
			.bss	140456	140456	0	0.0
			.data	2592	2592	0	0.0
			.text	1398864	1398864	0	0.0
	lock-app	default	(read/write)	2467856	2467856	0	0.0
			.bss	140304	140304	0	0.0
			.data	2600	2600	0	0.0
			.text	1426120	1426120	0	0.0
telink	light-switch-app	tlsr9518adk80d	(read/write)	797092	797092	0	0.0
			bss	70576	70576	0	0.0
			noinit	40416	40416	0	0.0
			text	565564	565564	0	0.0
	lighting-app	tlsr9518adk80d	(read/write)	816916	816916	0	0.0
			bss	71420	71420	0	0.0
			noinit	40416	40416	0	0.0
			text	581888	581888	0	0.0