[compiler-rt] Reapply "[compiler-rt] Default to Lit's Internal Shell" (PR #168232)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

My guess is changes in the process tree. I put up https://github.com/llvm/llvm-project/pull/170911 to fix this, but it hasn't been approved yet.

https://github.com/llvm/llvm-project/pull/168232