MFC r354043 (partial, by sjg):

Add support for hypervisor check on x86

Add ficl words for isvirtualized
and move ficl inb and outb words to ficl/x86/sysdep.c
so can be shared by i386 and amd64

Reviewed by: imp bdrewery
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22069

Note, only the stand/defs.mk changes were applied, as this fixes the
following error during buildworld for TARGET=pc98:

• cleandir_subdir_stand ---

rm: i386: is a directory

• [clean] Error code 1