x86/vmx: report failure if tests don't progress as expected

The test could have reported PASS even though it unexpectedly ended.
Make sure they FAIL.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <20170703175853.1939-3-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>