[llvm] [LoopVectorize] Refine runtime memory check costs when there is an outer loop (PR #76034)

[Florian Hahn via llvm-commits]

fhahn wrote:

> To be honest either approach is unsatisfactory, but I feel option 2) gives the reviewer a more fighting chance of seeing cause and effect!

IMO including a separate commit for precommitting  tests in a feature PR isn't ideal, as the default view in GH shows the diff for all changes compared to the main branch and when merging the PR all commits get squashed into one.

It's now possible to get something close to Phabricator's stacked reviews discussed here https://discourse.llvm.org/t/update-on-github-pull-requests/71540/146. 

https://github.com/llvm/llvm-project/pull/76034