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

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> You can either install it with pip

I'll do that, but I think LLDB should follow the example of MLIR here, so that pipeline scripts don't have hard-coded dependencies for individual projects:
https://github.com/llvm/llvm-project/blob/cee6e81dd2a393ebadac8b620679290851ae446b/.ci/monolithic-linux.sh#L41
https://github.com/llvm/llvm-project/blob/a58dd0e948040b75266b2ee02292a16ed7b2afd5/mlir/python/requirements.txt#L1-L3

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