[llvm] [SelectionDAG] Make `(a & x) | (~a & y) -> (a & (x ^ y)) ^ y` available for all targets (PR #137641)

[Iris Shi via llvm-commits]

el-ev wrote:

> > By the way, based on the tests, the existing folding on the X86 target doesn't seem to be working.
> 
> What do you mean by this?

Looking at the changes in llvm/test/CodeGen/X86/, the original patch should have achieved these optimizations, but it didn't.

https://github.com/llvm/llvm-project/pull/137641