Description:
------------
When providing a custom iterator to an ArrayObject, the iterator's constructor is not called on foreach.

Tested in the official php docker container:

https://github.com/docker-library/php/blob/b045ba7c51ceed8a495beb8ea7274df48a3c70e1/7.2/stretch/cli/Dockerfile

Test script:
---------------
class I extends ArrayIterator
{
    public function __construct(array $array = array(), $flags = 0)
    {
        exit(__FILE__ . ':' . __LINE__);
    }
}

$a = new ArrayObject([1, 2, 3], 0, I::class);
foreach ($a as $key => $value) {
    // do something
}


Expected result:
----------------
I expected the script to call I::__construct() and exit

Actual result:
--------------
The script finished without interruption