[clang] [llvm] Enable LLDB tests in Linux pre-merge CI (PR #94208)

[Med Ismail Bennani via cfe-commits]

medismailben wrote:

> if there's a PR with a clang label and it breaks an lldb test, then lldb reviewers get automatically added to the PR

I think it would be reasonable to have the CI add the last (or last few) git author(s) for the failing test, to help investigate the issue on the lldb side.

https://github.com/llvm/llvm-project/pull/94208