Remove entirely pointless assertion check that even causes a compiler bug on FreeBSD.

dtool/src/dtoolbase/neverFreeMemory.cxx

@@ -99,5 +99,5 @@ make_global_ptr() {
     // Someone else got there first.
     delete ptr;
   }
-  assert(_global_ptr != (NeverFreeMemory *)NULL);
 }
+