[llvm] [CI] include utils in monolithic scripts (PR #158090)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 requested changes to this pull request.

> What is this? This PR doesn't break anything/anyone because it's NFC because as nikita mentioned, currently monolithic doesn't actually install anything.

This as in the test that gets added. I'm pretty strongly opposed to a test that only runs in premerge. The test needs to be easily reproducible locally without a bunch of subtle undocumented CMake requirements.

https://github.com/llvm/llvm-project/pull/158090