[clang] [C++17] Support __GCC_[CON|DE]STRUCTIVE_SIZE (PR #89446)

[via cfe-commits]

cor3ntin wrote:

I think it makes sense to go with this patch and let target maintainers tweak the value subsequently.
It seems that trying to not provide a value unless explicitly specified by the target would be worse for library vendors as
`hardware_destructive_interference_size` is specified to exist unconditionally. 

https://github.com/llvm/llvm-project/pull/89446