[llvm] [InstCombine] Simplify a complex OR to XOR (PR #75129)

[Fujun Han via llvm-commits]

Peter9606 wrote:

> Precommit test First, then second commit is code change + test diff. It looks your test is the second commit.

No sure how it's shown in github PR, but I checked in my local environment that the order is correct, precommit first, then the patch.

https://github.com/llvm/llvm-project/pull/75129