[X86] Make _Int instructions the preferred instructon for the assembly parser...

[X86] Make _Int instructions the preferred instructon for the assembly parser and disassembly parser to remove inconsistencies between VEX and EVEX.

Many of our instructions have both a _Int form used by intrinsics and a form
used by other IR constructs. In the EVEX space the _Int versions usually cover
all the capabilities include broadcasting and rounding. While the other version
only covers simple register/register or register/load forms. For this reason
in EVEX, the non intrinsic form is usually marked isCodeGenOnly=1.

In the VEX encoding space we were less consistent, but usually the _Int version
was the isCodeGenOnly version.

This commit makes the VEX instructions match the EVEX instructions. This was
done by manually studying the AsmMatcher table so its possible I missed some
cases, but we should be closer now.

I'm thinking about using the isCodeGenOnly bit to simplify the EVEX2VEX
tablegen code that disambiguates the _Int and non _Int versions. Currently it
checks register class sizes and Record the memory operands come from. I have
some other changes I was looking into for D59266 that may break the memory check.

I had to make a few scheduler hacks to keep the _Int versions from being treated
differently than the non _Int version.

Differential Revision: https://reviews.llvm.org/D60441

llvm-svn: 358138