[llvm] [SelectionDAG] Add space-optimized forms of OPC_CheckPredicate (PR #77763)

[Wang Pengcheng via llvm-commits]

wangpc-pp wrote:

> Oddly, I'm seeing a test failure locally in `TableGen/address-space-patfrags.td` that stops happening when I revert this patch? Any clues as to why we wouldn't see this on bots? There isn't anything non-standard in my CMake other than I've enabled `-DLLVM_REVERSE_ITERATION=On`. Well, that and assertions + the runtimes build, but this happens even if I just build and test llvm.

This can be reproduced on my local machine, can you file an issue please? This should be backported to LLVM 18.

https://github.com/llvm/llvm-project/pull/77763