[clang] Add support for builtin_verbose_trap (PR #79230)

[Akira Hatanaka via cfe-commits]

ahatanak wrote:

> I think my last comment/question is still open? How/why did the symbol name end up dropping any llvm/clang component to avoid collisions with other names?

I dropped llvm/clang because I didn't think it would cause any collision in practice, but I don't think we have to try too hard to shorten the prefix.

https://github.com/llvm/llvm-project/pull/79230