Selectors: attr name in any NS on HTML elements are case-insensitive.

On elements in the HTML namespace in HTML documents,
selector matching of attribute names is ASCII-case insensitive
regardless of the attribute’s namespace.

This is a change proposed in whatwg/html#2694.
In the HTML spec before that change, this case-insensitivity only
applies to namespace-less attributes.

(Note that the HTML parser never crates namespaced attributes
on HTML elements, so using the DOM’s `setAttributeNS` is necessary
to create a situation where this change is observable.)

This change matches Firefox 53 and Chromium 58:
the number of passing/failing sub-tests didn’t change.

dom/nodes/ParentNode-querySelector-All-content.html

@@ -30,7 +30,7 @@
     <div class="attr-presence-div2" id="attr-presence-div2" align=""></div>
     <div class="attr-presence-div3" id="attr-presence-div3" valign="center"></div>
     <div class="attr-presence-div4" id="attr-presence-div4" alignv="center"></div>
-    <p id="attr-presence-p1"><a  id="attr-presence-a1" tItLe=""></a><span id="attr-presence-span1" TITLE="attr-presence-span1"></span></p>
+    <p id="attr-presence-p1"><a  id="attr-presence-a1" tItLe=""></a><span id="attr-presence-span1" TITLE="attr-presence-span1"></span><i id="attr-presence-i1"></i></p>
     <pre id="attr-presence-pre1" data-attr-presence="pre1"></pre>
     <blockquote id="attr-presence-blockquote1" data-attr-presence="blockquote1"></blockquote>
     <ul id="attr-presence-ul1" data-中文=""></ul>

dom/nodes/ParentNode-querySelector-All-content.xht

@@ -25,7 +25,7 @@
     <div class="attr-presence-div2" id="attr-presence-div2" align=""></div>
     <div class="attr-presence-div3" id="attr-presence-div3" valign="center"></div>
     <div class="attr-presence-div4" id="attr-presence-div4" alignv="center"></div>
-    <p id="attr-presence-p1"><a  id="attr-presence-a1" tItLe=""></a><span id="attr-presence-span1" TITLE="attr-presence-span1"></span></p>
+    <p id="attr-presence-p1"><a  id="attr-presence-a1" tItLe=""></a><span id="attr-presence-span1" TITLE="attr-presence-span1"></span><i id="attr-presence-i1"></i></p>
     <pre id="attr-presence-pre1" data-attr-presence="pre1"></pre>
     <blockquote id="attr-presence-blockquote1" data-attr-presence="blockquote1"></blockquote>
     <ul id="attr-presence-ul1" data-中文=""></ul>

dom/nodes/ParentNode-querySelector-All.js

@@ -45,6 +45,9 @@ function setupSpecialElements(doc, parent) {
 
   parent.appendChild(anyNS);
   parent.appendChild(noNS);
+
+  var span = doc.getElementById("attr-presence-i1");
+  span.setAttributeNS("http://www.example.org/ns", "title", "");
 }
 
 /*