Add unit test for CPUID save/restore.
Add unit test for CPUID save/restore.

Signed-off-by: Andrei Sandu <dbc21552912e46b041d86cfb2348c8cc4a9bf089@amazon.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker