[clang] [clang] Mark CWG2708, CWG2713, CWG2792 as resolved; sync CWG2947 status (PR #191174)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll commented:

Please change the title to something along the lines of "Add tests for CWG2708...", because you're not just adding statuses to CWG issues here.

https://github.com/llvm/llvm-project/pull/191174