[clang] Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (PR #92527)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Not the best one to be reviewing this, but the code generally looks good to me.

https://github.com/llvm/llvm-project/pull/92527