[ASTMatchers] Added BinaryOperator hasOperands matcher

Summary: Adds a matcher called `hasOperands` for `BinaryOperator`'s when you need to match both sides but the order isn't important, usually on commutative operators.

Reviewers: klimek, aaron.ballman, gribozavr2, alexfh

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80054