[llvm] [InstCombine] Simplify `add nsw/nuw i1` to `or disjoint i1` (PR #118221)

[Pedro Lobo via llvm-commits]

pedroclobo wrote:

Hey @dtcxzyw. This is one of my first contributions to LLVM. What kind of tests do you mean by "_tests to demonstrate that this change will improve the final codegen/analysis results_"?

https://github.com/llvm/llvm-project/pull/118221