[script] Fix use of freed list

A typo, I missed converting the user over to the freshly sorted list,
leaving it iterating over original but checking the sorted for termination
conditions.

src/cairo-script-surface.c

@@ -2003,7 +2003,7 @@ inactive (cairo_script_surface_t *surface)
 	cairo_list_t *operand;
 	int depth;
 
-	df = cairo_list_first_entry (&ctx->deferred,
+	df = cairo_list_first_entry (&sorted,
 				     struct deferred_finish,
 				     link);