KVM: selftests: Add test to verify KVM's supported XCR0

KVM: selftests: Add test to verify KVM's supported XCR0

Check both architectural rules and KVM's ABI for KVM_GET_SUPPORTED_CPUID
to ensure the supported xfeatures[1] don't violate any of them.

The architectural rules[2] and KVM's contract with userspace ensure for a
given feature, e.g. sse, avx, amx, etc... their associated xfeatures are
either all sets or none of them are set, and any dependencies are enabled
if needed.

[1] EDX:EAX of CPUID.(EAX=0DH,ECX=0)
[2] SDM vol 1, 13.3 ENABLING THE XSAVE FEATURE SET AND XSAVE-ENABLED
    FEATURES

Cc: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
[sean: expand comments, use a fancy X86_PROPERTY]
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Tested-by: Aaron Lewis <aaronlewis@google.com>
Link: https://lore.kernel.org/r/20230405004520.421768-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>