[llvm] [VPlan] Lower BranchOnTwoConds to chain of 2 simple branches. (PR #174016)

[via llvm-commits]

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

OK, this LGTM, thanks! Adding minor optional comments, plus the title could more strongly state the performance optimization nature of the patch. @luke97, @david-arm - any outstanding performance or other concerns?

https://github.com/llvm/llvm-project/pull/174016