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

[Dan Blackwell via llvm-commits]

DanBlackwell wrote:

@boomanaiden154 I can see some of the Darwin tests for sanitizers using `!(which sometool)` and backticks. Looking at the [RFC](https://discourse.llvm.org/t/rfc-enabling-the-lit-internal-shell-by-default/80179/29), the lit shell will not aim to support these.  What would be considered an appropriate workaround? `sh -c`?

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