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

[Vlad Serebrennikov via llvm-commits]

Endilll wrote:

Linux is passing now in 30 minutes. It's not clear how much overhead LLDB actually added, because other Linux builds on Clang changes are anywhere between 22 and 28 minutes.
I'm waiting for https://github.com/llvm/llvm-project/pull/94220 and news regarding failed MSVC build.

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