[SelectionDAG] define binops as a superset of commutative binops

[SelectionDAG] define binops as a superset of commutative binops

The test diffs show improved vector narrowing for integer min/max opcodes because
those were all absent from the list. I'm not sure if we can expose functional diffs
for all of the moved/added opcodes though.

It seems like we are missing an AVX512 opportunity to use 256-bit ops in place of
512-bit ops on some tests/targets, but I think that can be a follow-up.

Preliminary steps to make sure the callers are not misusing these queries:
rL361268
rL361547

Differential Revision: https://reviews.llvm.org/D62191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361701 91177308-0d34-0410-b5e6-96231b3b80d8