x86emul: adjustments to mem access / write logic testing

x86emul: adjustments to mem access / write logic testing

The combination of specifying a ModR/M byte with the upper two bits set
and the modrm field set to T is pointless - the same test will be
executed twice, i.e. overall things will be slower for no extra gain. I
can only assume this was a copy-and-paste-without-enough-editing mistake
of mine.

Furthermore adjust the base type of a few bit fields to shrink table
size, as subsequently quite a few new entries will get added to the
tables using this type.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>