[skip ci] Fix new closure dump syntax in test

ext/zend_test/tests/gh16230.phpt

@@ -9,12 +9,12 @@ $test = new _ZendTestFiber(function (): void {
 });
 $test->start();
 ?>
---EXPECT--
+--EXPECTF--
 array(1) {
   [0]=>
   array(2) {
     ["function"]=>
-    string(9) "{closure}"
+    string(%d) "{closure:%s:%d}"
     ["args"]=>
     array(0) {
     }