refactor

remove the free function entirely. all allocators are now expected to
implement reset instead. I reallized I never ever want to free an
individual allocation ever again. The forever_allocator is a special
case wherEreset is a no-op. The arena allocator was deleted. It will be
replaced soon.

test_dynamic_array.c

@@ -48,6 +48,5 @@ Test(dynamic_arrays, pop) {
             int num = dyn_array_pop(numbers);
             cr_assert_eq(num, 50-i);
         }
-        dyn_array_destroy(numbers);
     }
 }