[clang] [clang-tools-extra] [RecursiveASTVisitor] Assert we skip implicit instantiations. (PR #110899)

[Erich Keane via cfe-commits]

erichkeane wrote:

> > Please update the commit message/title in github to better reflect that you're ONLY adding the tests, else this LGTM.
> 
> Already updated the title, description, and commit message, but to be clear, it's not only adding a test, it's also adding the assertion, and that is reflected in the description. Are you still okay with that?

Ah, when I opened it, the commit message was still the old one!  Guess we crossed in the mail :)  The assertion is fine/I saw it.

https://github.com/llvm/llvm-project/pull/110899