[llvm] [VPlan] Untie tail folding from optimizeInductionLiveOutUsers. NFC (PR #207984)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon commented:

Hm, this looks correct to me, and seems to be a good idea, although we're using more memory and cycles to achieve the same result. I'm not sure if there is some way to represent FoldTail in VPlan, but maybe Florian can comment?

https://github.com/llvm/llvm-project/pull/207984