Do not try to enable new features in the %cr4 if running under hypervisor.  Apparently, hypervisors failed to filter out 'Standard Extended Features' report from CPUID, but deliver #gp when corresponding bit in %cr4 is toggled.
Do not try to enable new features in the %cr4 if running under
hypervisor.  Apparently, hypervisors failed to filter out 'Standard
Extended Features' report from CPUID, but deliver #gp when
corresponding bit in %cr4 is toggled.

This shall be reconsidered later, after hypervisors correct the bug.

Reported and tested by:	joel
Reviewed by:	avg
MFC after:	2 weeks

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase