Description:
------------
this bug is fixed already by me last night while try to to fix SEND_REF bug #70288

anyway, it's better to have a bug entry for the record 

Test script:
---------------
<?php
class MyTree implements ArrayAccess {
    public $children = array();

    public function offsetExists($offset) {
    }

    public function offsetUnset($offset) {
    }

    public function offsetSet($offset, $value) {
        $this->children[$offset] = $value;
    }

    public function offsetGet($offset) {
        return $this->children[$offset];
    }

}

$root = new MyTree();
$root[0] = new MyTree();
$a  = &$root[0];
$b  = &$root[0];
$c  = &$root[0];
$d  = &$root[0];
?>

Expected result:
----------------
non memory leak

Actual result:
--------------
[Wed Aug 19 10:43:57 2015]  Script:  '/tmp/1.php'
/home/huixinchen/opensource/github/php-src/Zend/zend_objects.c(161) :  Freeing 0x7F2E4145A4E0 (56 bytes), script=/tmp/1.php
[Wed Aug 19 10:43:57 2015]  Script:  '/tmp/1.php'
/home/huixinchen/opensource/github/php-src/Zend/zend_execute.c(543) :  Freeing 0x7F2E414730A8 (24 bytes), script=/tmp/1.php
Last leak repeated 3 times
=== Total 5 memory leaks detected ===