[clang] [Clang] Reuse tail-padding for more types that are not POD for the purpose of layout (PR #90462)

[John McCall via cfe-commits]

https://github.com/rjmccall approved this pull request.

This LGTM.  Please reach out to the Fuchsia and XL folks if you can, but we don't need to hold up the PR over it.

https://github.com/llvm/llvm-project/pull/90462