[X86][GlobalISel] Add limited ret lowering support to the IRTranslator.

Summary:
Support return lowering for i8/i16/i32/i64/float/double, vector type supported for 64bit platform only.
Support argument lowering for float/double types.

Reviewers: t.p.northover, zvi, ab, rovka

Reviewed By: zvi

Subscribers: dberris, kristof.beyls, delena, llvm-commits

Differential Revision: https://reviews.llvm.org/D29261

llvm-svn: 294173