[llvm] [SelectionDAG] Add space-optimized forms of OPC_CheckPredicate (PR #73488)

[Fangrui Song via llvm-commits]

MaskRay wrote:

One of the recent TableGen changes (likely `DAGISelMatcherEmitter.cpp`) may make output `*GenDAGISel.inc` non-deterministic. Things like DenseMap iterating needs some attention.

https://github.com/llvm/llvm-project/pull/73488