test: added test for push_front

src/arraylist.c

@@ -162,9 +162,9 @@ ArrayListErr arraylist_push_front(ArrayList *arr, void *data) {
 
     // No problem if array is full because  it grows if it's full
     memmove(
-        arr->buffer,
         arr->buffer + arr->elem_size,
-        (arr->len - 1) * arr->elem_size
+        arr->buffer,
+        (arr->len) * arr->elem_size
     );
 
     memcpy(