Description:
------------
Different DOMDocuments are always equal even if the 'XML' is different.



Reproduce code:
---------------
<?php
$dom1 = new DOMDocument();
$dom1->loadXML("<root><node/></root>");

$dom2 = new DOMDocument();
$dom2->loadXML("<root><node/></root>");

$dom3 = new DOMDocument();
$dom3->loadXML("<root><node type=\"blah\"/></root>");

if($dom1 == $dom2){
    print("dom1 == dom2\n");
}else{
    print("dom1 != dom2\n");
}

if($dom1 == $dom3){
    print("dom1 == dom3\n");
}else{
    print("dom1 != dom3\n");
}

?>

Expected result:
----------------
dom1 == dom2
dom1 != dom3

Actual result:
--------------
dom1 == dom2
dom1 == dom3