Support for vm32x/vm32y etc

[eschkufz]

vpgather uses an unsupported memory addressing form that uses xmm and ymm registers. As in:

vpgatherqq %ymm7,0x627100(,%ymm8,8),%ymm0

[eschkufz]

So this isn't too hard a fix... vm32x/vm32y are a new memory type VM32 and vm64y/vm64x are a new memory type VM64. Both are used exclusively with the vpgather instructions and no where else so they don't have a subtyping relation on anything else.

The assembly is exactly as you would expect. Just use the underlying register number to index into the sib table.

[eschkufz]

I guess this is really the short straw for me now. Might as well get after this.

[eschkufz]

This is going to touch a lot of code. I think I might want to go push a few simplifications to the source before getting too far into this. There's lots of places where code can be cut and simplified given all the changes that we've been making this last year.