[llvm] Revert "[Lit] Open sub-processes with text=`False`" (PR #196329)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM.

In a case like this I would think it's probably better to fix forward (ideally just let IBM propose a patch), but I guess this is fine too.

https://github.com/llvm/llvm-project/pull/196329