[llvm] [GISel] Funnel shift combiner port from SelectionDAG ISel to GlobalISel (PR #135132)

[Axel Sorenson via llvm-commits]

axelcool1234 wrote:

@mshockwave I have made a pre-commit test and a post-commit with the PR's title and description. Let me know if this is correct! And if so, then this can be merged :)

https://github.com/llvm/llvm-project/pull/135132