[InstCombine] Fix bug in canonicalization of Pow2 Tests (From: D152673)

D152673 Incorrectly didn't account for operand position in the `icmp`,
i.e it treated `icmp uge x, y` the same as `icmp uge y, x` which is
incorrect:
https://reviews.llvm.org/rG142f7448e770f25b774b058a7eab1f107c4daad9

The fix takes operand position into account. The new tests
exhaustively cover all operand positions for `ule`, `uge`, `ult`,
`ugt` (the set of predicates) and all transform verify with the new
commit.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D156058