[compiler-rt] [llvm] Revert "[runtimes] Allow building against an installed LLVM tree" (PR #113920)

[Nikolas Klauser via llvm-commits]

philnik777 wrote:

I'm landing this now, since everything seems to work fine and not being able to run tests being extremely disruptive.

@arichardson If you need any help reproducing the issue feel free to ask. I've tried multiple configurations and couldn't get the tests to ever run, so the issue is hopefully quite easy to fix.

https://github.com/llvm/llvm-project/pull/113920