[libcxx-commits] [libcxx] [libc++][NFC] Simplify copy and move lowering to memmove a bit (PR #83574)

[Konstantin Varlamov via libcxx-commits]

https://github.com/var-const approved this pull request.

LGTM. Please check with @ldionne before submitting in case he has more feedback.

https://github.com/llvm/llvm-project/pull/83574