[compiler-rt] [sanitizer] Use close_range on Linux to close FDs in StartSubprocess (PR #191450)

[Paweł Bylica via llvm-commits]

https://github.com/chfast commented:

This is implementation where we explicitly guard all usage of `internal_close_range` with macros like `SANITIZER_LINUX` or `SANITIZER_USE_CLOSE_RANGE`.

I think much cleaner implementation is to implement the fallback inside the `internal_close_range`. I didn't do it because I wasn't sure if this not against established practice.

https://github.com/llvm/llvm-project/pull/191450