Description:
------------
A simple XPath that matches namespaces should return all nodes, however, it only returns every second one.

Using the below link I confirmed this issue for all versions of PHP 5.0.0 - 5.6.9

http://3v4l.org/4qZhu

Test script:
---------------
<?php
$doc = new DOMDocument('1.0', 'UTF-8');
$doc->loadXML('<root xmlns:ns="foo" ns:id="1"> <one/> <two/> <three/> <four/> <five/> </root>');
$finder = new DOMXPath($doc);
$nodes = $finder->query("//node()[namespace::ns]");
foreach ($nodes as $n) {
  var_dump($doc->saveXML($n));
}

Expected result:
----------------
string(78) "<root xmlns:ns="foo" ns:id="1"> <one/> <two/> <three/> <four/> <five/> </root>"
string(6) "<one/>"
string(6) "<two/>"
string(8) "<three/>"
string(7) "<four/>"
string(7) "<five/>"

Actual result:
--------------
string(78) "<root xmlns:ns="foo" ns:id="1"> <one/> <two/> <three/> <four/> <five/> </root>"
string(6) "<two/>"
string(7) "<four/>"