[clang] [REAPPLY][Clang-Repl] Add support for out-of-process execution. #110418 (PR #144064)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

@SahilPatidar can you address this in a way that works for the intended purpose of this patch?

https://github.com/llvm/llvm-project/pull/144064