fix crash when object malloc_size no greater than zero

Classes/GlobalStateExplorers/FLEXInstancesTableViewController.m

@@ -31,7 +31,9 @@
             // Note: objects of certain classes crash when retain is called. It is up to the user to avoid tapping into instance lists for these classes.
             // Ex. OS_dispatch_queue_specific_queue
             // In the future, we could provide some kind of warning for classes that are known to be problematic.
-            [instances addObject:object];
+            if (malloc_size((__bridge const void *)(object)) > 0) {
+                [instances addObject:object];
+            }
         }
     }];
     FLEXInstancesTableViewController *instancesViewController = [[self alloc] init];