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

[Dan Blackwell via llvm-commits]

DanBlackwell wrote:

Hi @boomanaiden154, it looks like a good number of these tests failing are specific to Darwin - if you need any help or have a patch to review for these could you please tag me, @ndrewh, @wrotki or @thetruestblue? Thanks 

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