[clang] [clang] make __buildin_object_size and __builtin_dynamic_object_size compatible with GCC's constexpr implementation (PR #196377)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

@tbaederr : can you help point the author in the right direction here for the bytecode interpreter? 

This seems right to me?  But I'd like folks with more knowledge to do the review.

https://github.com/llvm/llvm-project/pull/196377