[llvm] [VPlan] Use VPlan operand order for VPBlendRecipes. (PR #139475)

[via llvm-commits]

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

This LGTM, although it might be better to isolate the operand reordering part into a separate (non NFC) patch dedicated to it alone.

https://github.com/llvm/llvm-project/pull/139475