[clang] [Clang] Avoid assertion failure for initialized extern aliases (PR #223124)

[via cfe-commits]

keepyixiao wrote:

> Sorry for the delay!
See the comment, please add a release note for the fix once comment is resolved and make sure to disclose any AI usage as per our AI [policy](https://llvm.org/docs/AIToolPolicy.html).

Thanks for the review! I've addressed the comment and added a release note.I've also disclosed the AI assistance in the PR description.

https://github.com/llvm/llvm-project/pull/223124