[llvm] [InstCombine] Fold `(icmp eq/ne (xor x, y), C1)` even if multiuse (PR #87275)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Can you please move the foldSelectValueEquivalence() changes into a separate PR (to land first)?

https://github.com/llvm/llvm-project/pull/87275