Revert "Add mDNS shutdown (#9621)"

[andy31415]

This reverts commit 3da26cf.

Tizen builds seem broken since this change:

2021-09-13 15:22:31 INFO
/__w/connectedhomeip/connectedhomeip/out/tizen-arm-light/../../examples/lighting-app/linux/third_party/connectedhomeip/src/lib/mdns/Discovery_ImplPlatform.h:46:
undefined reference to `chip::Mdns::ChipMdnsShutdown()'
409
2021-09-13 15:22:31 INFO    collect2: error: ld returned 1 exit status

[github-actions]

Size increase report for "gn_qpg-example-build" from 7bc58b9

File	Section	File	VM
chip-qpg6100-lighting-example.out	.text	-16	-16

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-qpg6100-lighting-example.out and ./pull_artifact/chip-qpg6100-lighting-example.out:

sections,vmsize,filesize
[Unmapped],0,16
.shstrtab,0,1
.debug_aranges,0,-16
.debug_ranges,0,-16
.text,-16,-16
.debug_frame,0,-32
.debug_line,0,-38
.debug_abbrev,0,-47
.symtab,0,-80
.debug_loc,0,-105
.debug_str,0,-118
.debug_info,0,-136
.strtab,0,-153

Comparing ./master_artifact/chip-qpg6100-lighting-example.out.map and ./pull_artifact/chip-qpg6100-lighting-example.out.map:

BLOAT EXECUTION FAILED WITH CODE 1:
bloaty: unknown file type for file './pull_artifact/chip-qpg6100-lighting-example.out.map'

[github-actions]

Size increase report for "nrfconnect-example-build" from 7bc58b9

File	Section	File	VM
chip-shell.elf	rodata	-8	-8
chip-shell.elf	text	-16	-16
chip-lock.elf	device_handles	-4	-4
chip-lock.elf	rodata	-8	-8
chip-lock.elf	text	-12	-12

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
.shstrtab,0,1
rodata,-8,-8
.debug_aranges,0,-16
.debug_ranges,0,-16
text,-16,-16
.debug_loc,0,-27
.debug_frame,0,-32
.debug_line,0,-36
.debug_abbrev,0,-79
.symtab,0,-80
.debug_str,0,-117
.strtab,0,-153
.debug_info,0,-173

Comparing ./master_artifact/chip-lock.elf and ./pull_artifact/chip-lock.elf:

sections,vmsize,filesize
.shstrtab,0,1
device_handles,-4,-4
rodata,-8,-8
text,-12,-12
.debug_aranges,0,-16
.debug_ranges,0,-16
.debug_frame,0,-32
.debug_line,0,-41
.debug_abbrev,0,-47
.debug_loc,0,-51
.symtab,0,-80
.debug_str,0,-117
.debug_info,0,-136
.strtab,0,-153