Description:
------------
Originally found as https://3v4l.org/LtSmU - it seems the new SimpleXMLIterator broke something wrt iterator_iterator, there is a mismatch in counts, and count(IteratorIterator(DOMNodeList)) throws an Exception that doesn't seem necessary

Test script:
---------------
$XML = <<< XML
<root>
  <item>1</item>
  <item>2</item>
  <item>3</item>
</root>
XML;

$dom = new DomDocument();
$dom->loadXml($XML);
$items = $dom->getElementsByTagName('item');

echo "Count: ".count($items). PHP_EOL;
$it = new IteratorIterator($items);
$c = iterator_count($it);
echo "Count: $c", PHP_EOL;


Expected result:
----------------
Count: 3
Count: 3

Actual result:
--------------
Count: 3
Count: 4