[llvm] [InstCombine] Canonicalize `extractvalue + select` (PR #84686)

[Nikita Popov via llvm-commits]

nikic wrote:

@dtcxzyw If it is viable from a compile-time perspective, we could change the fold to use InstSimplify instead of ConstantFolding...

https://github.com/llvm/llvm-project/pull/84686