[clang] Reland Print library module manifest path again (PR #84881)

[Mark de Wever via cfe-commits]

mordante wrote:

> Can we also have a fallback check for stdlibs that don't have a `.so` version (such as embedded)? Something as simple as:
> 
> ```c++
>     std::string lib = GetFilePath("libc++.so", TC);
>     if (lib.empty())
>       lib = GetFilePath("libc++.a", TC);
> ```

Excellent point! thanks!

https://github.com/llvm/llvm-project/pull/84881