[llvm] [InstCombine] Fold `select Cond, not X, X` into `Cond ^ X` (PR #93591)

[via llvm-commits]

goldsteinn wrote:

Im somewhat partial to https://github.com/llvm/llvm-project/pull/90089. In general would prefer to use existing analysis logic (`isImpliedCondition...`) than this bespoke function.
Is there anything this function can do that other cant?

https://github.com/llvm/llvm-project/pull/93591