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

[via cfe-commits]

yronglin wrote:

> I think this looks ok, I'd love it if @cor3ntin took another look, but I'm as happy as before.

Thanks for your review!

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