[llvm] [VPlan] Move recording of Inst->VPValue to VPRecipeBuilder (NFCI). (PR #84464)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

> Independent of this patch: should VPRecipeBuilder (or some other sub/class thereof) be confined to initial VPlan construction from LLVM-IR, excluding construction of recipes during VPlan-to-VPlan transformations?

Yes, `VPRecipeBuilder` ( not to be confused with `VPBuilder`) is only used for initial construction. We should split of the logic to create the initial VPlan to a separate helper, and only instantiate `VPRecipeBuilder` there

https://github.com/llvm/llvm-project/pull/84464