[llvm] [VectorCombine] foldSelectShuffle - remove extra adds of old shuffles to worklist (PR #127999)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

> my guess is this was to ensure that the instructions got erased first to help cleanup unused instructions, but eraseInstruction should handle this now.

Yeah I think that was why it was added. It looks like it isn't needed any more, if the tests do not change.

LGTM, thanks

https://github.com/llvm/llvm-project/pull/127999