[llvm] [ci] diff with main merge-base (PR #69308)

[Mikhail Goncharov via llvm-commits]

metaflow wrote:

Two examples of main..HEAD diff for PRs with multiple commits

https://buildkite.com/llvm-project/github-pull-requests/builds/7973
https://buildkite.com/llvm-project/github-pull-requests/builds/8152


https://github.com/llvm/llvm-project/pull/69308