[clang] [Clang-Repl] Adds custom lambda in launchExecutor and PID retrieval (PR #152562)

[Abhinav Kumar via cfe-commits]

kr-2003 wrote:

> This change is also breaking Bazel. After fixing the missing dependency in #152681, I'm now getting
> 
> ```
> Specified executor invalid: /var/lib/buildkite-agent/.cache/bazel/_bazel_buildkite-agent/c9d34ded3a9d94cc250207948aceadfc/execroot/__main__/bazel-out/k8-fastbuild/bin/bin/llvm-jitlink-executor
> ```
> 
> which is raised in `RemoteJITUtils.cpp`.
> 
> https://buildkite.com/llvm-project/upstream-bazel/builds/145926/steps/canvas?sid=01988921-967b-46f5-91ce-2498c8480786
> 
> To reproduce, run `bazel test --config=generic_clang @llvm-project//clang/unittests:interpreter_tests`.

I use this code for removing the extra dirs for calculating the executable paths:
https://github.com/llvm/llvm-project/blob/672f82a2ef82d26f2bff024300c4658ab593c93f/clang/unittests/Interpreter/OutOfProcessInterpreterTests.cpp#L50

here

https://github.com/llvm/llvm-project/blob/672f82a2ef82d26f2bff024300c4658ab593c93f/clang/unittests/Interpreter/OutOfProcessInterpreterTests.cpp#L55-L60

ALso, I can see 2 ``bin``s in the executor path. 
```
..../bazel-out/k8-fastbuild/bin/bin/llvm-jitlink-executor
```

So, for bazel, I think the folder structure is quite different than expected. 

https://github.com/llvm/llvm-project/pull/152562