[llvm] [InstCombine] Canonicalize `icmp ult (add X, C2), C` expressions (PR #95649)

[via llvm-commits]

goldsteinn wrote:

> The key question here is whether this is the right canonicalization direction -- do we prefer a mask check over a range check? I guess if @dtcxzyw's tests don't show regressions from this, then this direction is fine.

W.o `nuw`/`nsw` would def think mask check is better. W/ the flags could imagine the other way around though.

https://github.com/llvm/llvm-project/pull/95649