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

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

I would normally have no issue making the changes needed to other projects, and I mostly try to do that.
But lldb sets itself apart in how hard it is to get a project setup going, and how impactful it is.

It's a bit concerning when the changes needed are quite trivial, for example just changing diagnostics expectations, but you have no other way to test that.

I think the lldb pre-commit CI would at least help here, for trivial changes, we can keep trying to fix and verifying it by pushing to the PR, no changes needed on developer setup side.

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