[llvm] [IR][InstCombine] Add `N{U,S}WAddLike` matchers. (PR #86082)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Missing fold: https://alive2.llvm.org/ce/z/jZgVSn

https://github.com/llvm/llvm-project/blob/2096f37d7a580a4b4ddce2a44abb80ff90f273ee/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp#L960-L974

https://github.com/llvm/llvm-project/pull/86082