[llvm] [DAGCombine] Correctly extend the constant RHS in `TargetLowering::SimplifySetCC` (PR #152862)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

@asmok-g Sorry to hear that my change seems to be causing more issues! Would it be possible to attach more details about how to reproduce and whether there is any information produced when clang crashes? I'm very unfamiliar with `lldb` and I'm having trouble reproducing this issue locally. 

https://github.com/llvm/llvm-project/pull/152862