LibC: Notify UE at the start of free() instead of at the end

This way, if we end up deallocating an entire ChunkedBlock, UE doesn't
get confused thinking the freed pointer has never been allocated.

Libraries/LibC/malloc.cpp

@@ -377,8 +377,8 @@ static void free_impl(void* ptr)
 {
     if (s_profiling)
         perf_event(PERF_EVENT_FREE, reinterpret_cast<FlatPtr>(ptr), 0);
-    free_impl(ptr);
     ue_notify_free(ptr);
+    free_impl(ptr);
 }
 
 void* calloc(size_t count, size_t size)