[clang] [clang] Fix a crash issue that caused by handling of fields with initializers in nested anonymous unions (PR #113049)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic approved this pull request.

LGTM

I'm a little concerned this is going to lead to other crashes due to exposing more codepaths to "invalid" decls. But it seems like it's doing the right thing in the given cases.

https://github.com/llvm/llvm-project/pull/113049