[clang] [clang-repl] Simplify the logic around out of process execution. NFC (PR #175322)

[Rainer Orth via cfe-commits]

rorth wrote:

> I am interested in fixing the current setup -- can you spell out the name and the complete location for the orc runtime?

Sure: `lib/clang/22/lib/sunos/liborc_rt-x86_64.a`.

https://github.com/llvm/llvm-project/pull/175322