[clang] [clang][Sema] Diagnose exceptions only in non-dependent context in discarded `try/catch/throw` blocks (PR #139859)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Mostly happy, handful of changes but none are design changes.

https://github.com/llvm/llvm-project/pull/139859