[llvm] [InstCombine] Resolve TODO: Remove one-time check if other logic operand (Y) is constant (PR #77973)

[Jessica Clarke via llvm-commits]

jrtc27 wrote:

> > You have a commit to precommit tests, but the second commit doesn't touch any of the tests?
> > Also the precommit commit will need to be its own PR otherwise it'll get squashed when merging
> 
> I thought squashed while merging is what we wanted?

Not when you *want* two commits, like in this case, such that the history clearly shows the test differences.

https://github.com/llvm/llvm-project/pull/77973