Description:
------------
Using the LIBXML_HTML_NOIMPLIED predefined constant in the DomDocument class has unexpected results.

The nodeValue of any first DOMNodeList item always contains all the values of every node list item in the collection only when the optional LIBXML_HTML_NOIMPLIED predefined constant is passed to the loadHTML() method.

I am currently running:
- PHP Version 5.5.8
- libxml Version 2.9.1

Test script:
---------------
$html = '<h1>Foo</h1><h2>Bar</h2><p>lorem ipsum</p>';
$dom = new \DomDocument();
$dom->loadHTML($html, LIBXML_HTML_NOIMPLIED);
$nodes = $dom->getElementsByTagName('*');
echo $nodes->item(0)->tagName . ' -> ' . $nodes->item(0)->nodeValue . '<br/>';
foreach ($nodes as $node) {
    echo $node->tagName . ' -> ' . $node->nodeValue . '<br/>';
}

Expected result:
----------------
h1 -> FooBarlorem ipsum
h1 -> FooBarlorem ipsum
h2 -> Bar
p -> lorem ipsum

Actual result:
--------------
h1 -> Foo
h1 -> Foo
h2 -> Bar
p -> lorem ipsum