[clang] [clang][AST] Invalidate DecompositionDecl if it has invalid initializer. (PR #72428)

[Haojian Wu via cfe-commits]

hokein wrote:

> We need a release note and please add a more detailed summary. A description of the problem being solved and the solution to the fix provides.

Done. 

https://github.com/llvm/llvm-project/pull/72428