Description:
------------
After cloning an instance of SplObjectStorage the number of objects 
which can be retrieved with count() is very high and foreach() causes a 
segfault.

Reproduce code:
---------------
class Foo {}

$storageA = new \SplObjectStorage();
$storageA->attach(new \Foo);
$storageA->attach(new \Foo);

echo ("Count storage A: " . count($storageA));
foreach ($storageA as $object) {
	echo ' x ';
}

$storageB = clone $storageA;
echo ("Count storage B: " . count($storageB));
foreach ($storageB as $object) {
	echo ' x ';
}


Expected result:
----------------
Count storage A: 2 x x Count storage B: 2 x x

Actual result:
--------------
Count storage A: 2 x x Count storage B: 1953394499