[llvm] [VPlan] Dispatch to multiple exit blocks via middle blocks. (PR #112138)

[David Sherwood via llvm-commits]

https://github.com/david-arm commented:

LGTM! Thanks a lot for all the changes @fhahn. I have a couple of minor comments, but these can be addressed before merging.

https://github.com/llvm/llvm-project/pull/112138