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

[Mark de Wever via cfe-commits]

mordante wrote:

> > The file we're looking for is `modules.json`; Renaming it `libc++.modules.json` like `.so` / `.a` file might be a better idea which could avoid name clashes when installed in `/usr/lib`.
> 
> but i didn't rename it, it was with the libc++ prefix directly :/

Good point I did :-/ It seems we originally talked about `modules.json` and later mentioned using the libname. @ChuanqiXu9 I prefer to keep the current name `libc++.modules.json` and adjust clang. WDYT?

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