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

[Hubert Tong via cfe-commits]

hubert-reinterpretcast wrote:

> @hubert-reinterpretcast There were none, now I've added some: https://github.com/llvm/llvm-project/blob/cf8be1bac0eb37caaaecd47cb463ca58ee0fbe59/clang/test/Layout/itanium-padded-bit-field.cpp

Thanks. I am a bit concerned that the fix to match the Itanium ABI on the oversized-bitfield cases actually introduces a compatibility issue with GCC.

See https://godbolt.org/z/c85f8s9Ex (extracted from a test in this patch). GCC passes with `-DOLD_ABI=true` (and not with `-DOLD_ABI=false`.

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