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

[Nikita Popov via llvm-commits]

nikic wrote:

You need the simplest possible test (no vectors...) that does not fold before your changes and folds after your changes. Please find this test on your own.

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