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

[Haojian Wu via cfe-commits]

https://github.com/hokein commented:

Attaching an empty RecoveryExpr as an initializer to indicate that initialization was attempted but failed seems reasonable to me. I'll leave the approval to @efriedma-quic.

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