2c3bbac0c7
This patch also adds a new optimization to `std::move`. It unwraps three `reverse_iterator`s if the wrapped iterator is a `contiguous_iterator` and the iterated type is trivially_movable. This allows us to simplify `ranges::move_backward` to a forward to `std::move` without any pessimization. Reviewed By: var-const, #libc Spies: libcxx-commits, mgorny Differential Revision: https://reviews.llvm.org/D126616