Initial vscl and vmmul in x86 jit

Neither is very optimal, but vmmul at least is definitely faster even like this than the interpreter (gained maybe 6% fps in Crisis Core, I think.)  Probably mostly because prefix checks are compiled out, etc.

Was trying to move a few more things to jit to see what's causing the 32-bit-only weirdness in Kingdom Hearts.

I also tried a vmin/vmax using CMPSS/ANDPS/ANDNPS/ORPS/etc. but somehow got it very wrong....

-[Unknown]