allot/rand: switch vm-vp-1G/cpu-hotplug.yaml to vm-vp-2G

cpu-hotplug needs more than 1G memory, switch it to suitable tbox.
fix the following issue:
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[    3.010139] Kernel panic - not syncing: Out of memory and no killable processes...
[    3.010139]
[    3.011128] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0 #1
[    3.011128] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[    3.011128] Call Trace:
[    3.011128]  dump_stack+0x5c/0x7c
[    3.011128]  panic+0xd5/0x242
[    3.011128]  ? dump_header+0x193/0x2ac
[    3.011128]  out_of_memory+0x3cb/0x4d0
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Signed-off-by: Chen Rong <[email protected]>

Signed-off-by: Philip Li <[email protected]>