[llvm] [VPlan] Implement VPlan-based cost model for VPReduction, VPExtendedReduction and VPMulAccumulateReduction. (NFC) (PR #113903)

[Sander de Smalen via llvm-commits]

sdesmalen-arm wrote:

I see the PR has "NFC" in the title, which is not correct because the behaviour may be subtly different with these code-changes. Can you please remove it?

https://github.com/llvm/llvm-project/pull/113903