[llvm] Simplify `(a % b) lt/ge (b-1)` into `(a % b) eq/ne (b-1)` (PR #72504)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Implementation looks good, just a note on the tests.

https://github.com/llvm/llvm-project/pull/72504