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

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> > @Michael137 This is for Linux. Windows works the same way just below those lines:
> > https://github.com/llvm/llvm-project/blob/9a7bd8a60f03595be5d42315790df6d409f81091/.ci/generate-buildkite-pipeline-premerge#L253-L255
> 
> Ah, so what would the issue be with just adding more specific `check-lldb-*` targets, rather than all of `check-lldb`?

Those more specific targets will be used instead of `check-lldb` every time lldb is tested, e.g. when there are just lldb changes in the PR, and Clang is not touched.

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