[llvm-branch-commits] [llvm] premerge: Enable on Linux and Windows (PR #147581)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM barring removing the test trigger from `llvm/README.txt`. Given that we're now planning on using this in the release branch too, do you want all changes going into `premerge.yaml` to also be backported?

https://github.com/llvm/llvm-project/pull/147581