[llvm] [InstCombine] Fold `select Cond, not X, X` into `Cond ^ X` (PR #90089)

[via llvm-commits]

goldsteinn wrote:

> > TEST 'BOLT :: RISCV/unnamed-sym-no-entry.c' FAILED
> 
> The test failure is unrelated with this patch.

I've also seen that test fail on a few buildbots.

https://github.com/llvm/llvm-project/pull/90089