[AMDGPU] Make some VOP3 insts commutable

[AMDGPU] Make some VOP3 insts commutable

Note, only src0 and src1 will be commuted if the isCommutable flag
is set. This patch does not change that, it just makes it possible
to commute src0 and src1 of some U/I/B vop3 instructions.

This patch revises d35d8da7d6ac6c08578ec0569b072292631691e0.
It contains the commute opportunities excluding float insts

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D101474

Change-Id: I62938173d750453839f2457a3851661a29135faf