Fix omission: if we receive a guest trap on CR0, and if the original
instruction would have resulted in Long Mode being enabled, we need to
manually enable Long Mode ourselves. We were already doing that correctly
in setstate, but not in the CR0 trap handler.
Problem initially reported by Aymeric Vincent; ArchLinux wouldn't boot,
now it does and works correctly.
While here, add CR0_ET in the CR0 mask, for the associated shadow to
be taken into account. Normally this shadow bit shouldn't be necessary,
but for now I keep it regardless.
UnifiedSplitRaw
