[X86][MS-compatability][llvm] allow MS TYPE/SIZE/LENGTH operators as a part of...

[X86][MS-compatability][llvm] allow MS TYPE/SIZE/LENGTH operators as a part of a compound expression

This patch introduces X86AsmParser with the ability to handle the aforementioned ops within compound "MS" arithmetical expressions.
Currently - only supported as a stand alone Operand, e.g.:
"TYPE X"
now allowed :
"4 + TYPE X * 128"

Clang side: https://reviews.llvm.org/D31174

Differential Revision: https://reviews.llvm.org/D31173

llvm-svn: 298425