[clang] [clang][Sema] Fix crash on decomposition decl missing initializer (PR #210151)

[Erich Keane via cfe-commits]

erichkeane wrote:

> > Just needs a release note, else this LGTM.
> 
> [22ca91c](https://github.com/llvm/llvm-project/commit/22ca91ce27af31f579a8a770a4d584f47bcc607f) (PR #127924) introduced the crash and landed a week ago on the dev branch. The new diagnostic didn't ship yet. Should we still add 'crash fix' to release notes or rather skip it?

A "week ago" is still old enough to have made it into the 23.0 branch!  So we still need a release note HERE, but we probably also want to cherry-pick this to the release branch.

Also, see you have a formatter error that you have to fix, linux test seems unrelated.

https://github.com/llvm/llvm-project/pull/210151