[llvm] VPlan: use worklist in simplifyRecipes (PR #93998)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> If it is not too much extra work, it would probably also be good to introduce the worklist as NFC commit without test changes and then replace the patterns.

Not sure what you mean by introducing the worklist as an NFC. Doesn't the introduction of worklist mean that we return candidates for further simplification, reducing recursively, and by definition, the change has higher simplification power? I might be able to introduce the worklist without any _test changes_, that isn't technically an NFC, with some difficulty; however, I don't see the value of such a patch.

https://github.com/llvm/llvm-project/pull/93998