[llvm] [DenseMap] memcpy buckets with trivial copy constructor and destructor. NFC (PR #224193)

[via llvm-commits]

aokblast wrote:

Hi, this breaks build on FreeBSD. We still ship _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR in our base. We would like to resolve this by having libcxx.so.2 in our base. But it is not happen for now.

https://github.com/llvm/llvm-project/pull/224193