Reapply "[compiler-rt] Default to Lit's Internal Shell (#168232)"
This reverts commit c90fb56b41cfaaee448700f6b068c830d8d0b5bd.
The failures identified in the revert commit have noe been fixed:
1. 4bc783be2dab2b0b2b3010158891e44a2b4ee991
2. 126462035a1eb7adeb97f6beac48b6bddac65d09
3. d7307f458cd3522470859ce0cee8d47d37a70670