[clang] [llvm] Add source file name for template instantiations in -ftime-trace (PR #98320)

[Ilya Biryukov via cfe-commits]

https://github.com/ilya-biryukov commented:

Thanks for adding an optional flag for this.
Given that the profiles are 2-3x larger now, this seems very much warranted.

Mostly LG, but I did have some questions and suggestions. PTAL.

https://github.com/llvm/llvm-project/pull/98320