[clang] [clang][modules] Print library module manifest path. (PR #76451)

[Mark de Wever via cfe-commits]

mordante wrote:

I had looked at `-print-search-dirs` but it seems buggy. For example, it ignores the `-stdlib` flag to the compiler invocation. Solving this seems a lot of work. So didn't want to add new features to that code.

https://github.com/llvm/llvm-project/pull/76451