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

[Michael Buch via llvm-commits]

Michael137 wrote:

Worth a shot i guess. Though it could be somewhat disruptive if we do in fact have flaky tests. I don't think we need to run *all* tests. Should we just run the tests for the LLDB C++ language plugin (i.e., the part of LLDB that invokes Clang and the JIT). And then we could expand the set of tests from there?

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