[llvm] [libc] [lldb] [mlir] [clang] [NFC][ObjectSizeOffset] Use classes instead of std::pair (PR #76882)

[Johannes Doerfert via cfe-commits]

https://github.com/jdoerfert commented:

Generally, getting rid of the pair is great.
I am unsure I understand why we do the base template rather than inheritance. Where is the base template used? If we do inheritance we could avoid duplicating of members and provide default impls that work with many things, e.g., all operator== are the same.


https://github.com/llvm/llvm-project/pull/76882