Method reset

tests/fl/stl/allocator_move.cpp:53–60

        int deallocations = 0;

        void reset() {
            copy_constructs = 0;
            move_constructs = 0;
            copy_assigns = 0;
            move_assigns = 0;
            allocations = 0;
            deallocations = 0;
        }
    };

    Stats* stats;  // Non-owning pointer to shared stats