CVE-2018-12126, CVE-2018-12127, CVE-2018-12130

The bit is set when microcode provides the mechanism to invoke a flush
of various exploitable CPU buffers by invoking the VERW instruction.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>
(cherry picked from commit 538d8735)

Conflicts:
	src/cpu_map/x86_features.xml
            - no CPU map split downstream

	tests/cputestdata/x86_64-cpuid-Xeon-Platinum-8268-guest.xml
	tests/cputestdata/x86_64-cpuid-Xeon-Platinum-8268-host.xml
            - test data missing downstream

	tests/cputestdata/x86_64-cpuid-Xeon-E3-1225-v5-guest.xml
	tests/cputestdata/x86_64-cpuid-Xeon-E3-1225-v5-host.xml
            - intel-pt feature is missing downstream
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>