Add (untested!) SSSE3, SSE4.1, SSE4.2 instructions

Add (untested!) SSSE3, SSE4.1, SSE4.2 instructions

Add the SSSE3, SSE4.1 and SSE4.2 instruction sets.  Change \332 to be
a literal 0xF2 prefix, by analog with \333 for 0xF3 prefix (the
previous \332 flag changed to \335).  This is necessary to get the REX
prefix in the right place for instructions that use it.

We are going to have to go in and change existing instruction patterns
which use these, as well.