Description:
------------
this bug only can be triggered with concurrent requests. 

like using ab -n 1000 -c 50 



Test script:
---------------
<?php

class A {
    public function test($a = array("okey")) {
    }
}


eval ("class B extends A { public function test() {} }");


Expected result:
----------------
none segfault

Actual result:
--------------
segfault with a backtrace similar to #70631