[libcxx-commits] [libcxx] [libc++][hardening] Add `_LIBCPP_ASSERT_NON_NULL` to check for null pointers (PR #71428)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne approved this pull request.

This basically LGTM with a few minor comments.

https://github.com/llvm/llvm-project/pull/71428