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

[Min-Yih Hsu via llvm-commits]

https://github.com/mshockwave commented:

Please refrain from force push unless it's necessary: https://www.llvm.org/docs/GitHub.html#rebasing-pull-requests-and-force-pushes.
Append new commits instead, as they're all gonna be squash into one at the end.

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