[clang] [llvm] [clang][LLVM Demangler] Add an assertion that validates that all mang… (PR #111391)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Since this is being done as an assert, this is something that really only applies during debug mode.  I dont think this compiler flag makes sense because of it.

IMO, this should either be a preprocessor macro to enable (so it is a build config), or a diagnostic that happens all the time (perhaps whose default changes?).

https://github.com/llvm/llvm-project/pull/111391