KVM: selftests: Add MONITOR/MWAIT quirk test

Add a test to verify the "MONITOR/MWAIT never fault" quirk, and as a
bonus, also verify the related "MISC_ENABLES ignores ENABLE_MWAIT" quirk.

If the "never fault" quirk is enabled, MONITOR/MWAIT should always be
emulated as NOPs, even if they're reported as disabled in guest CPUID.
Use the MISC_ENABLES quirk to coerce KVM into toggling the MWAIT CPUID
enable, as KVM now disallows manually toggling CPUID bits after running
the vCPU.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220608224516.3788274-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>