[clang] [Clang] Wide delimiters ('{{{') for expect strings (PR #77326)

[Erich Keane via cfe-commits]

erichkeane wrote:

> I think I've followed all the steps in https://llvm.org/docs/GitHub.html#landing-your-change except performing the actual merge (or squash), for which I lack write permissions. Is there anything else for me to do here?

Nope!  I'll put this on my list to merge when teh tests all pass.

https://github.com/llvm/llvm-project/pull/77326