[llvm] [ci] Don't add more check targets if "check-all" is present (PR #110277)

[Vlad Serebrennikov via llvm-commits]

Endilll wrote:

> > Can't we do something along the lines of `check-compiler-rt` instead of `check-all`? That would be much simpler than your change.
> 
> Can you expand on this suggestion? I don't quite understand. What does `check-compiler-rt` do?

Sure. I mean a dedicated target to run compiler-rt tests, like we have `check-clang` or `check-cxx` for Clang and libc++ tests respectively.

https://github.com/llvm/llvm-project/pull/110277