KVM: selftests: Rename 'get_cpuid_test' to 'cpuid_test'

In preparation to reusing the existing 'get_cpuid_test' for testing
"KVM_SET_CPUID{,2} after KVM_RUN" rename it to 'cpuid_test' to avoid
the confusion.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220117150542.2176196-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>