Use simple string comparison for query string

and forbid query string on stun/stuns
see #2996 (comment)

webrtc.html

@@ -3092,14 +3092,10 @@ <h4>
                         [[!RFC7065]] section 3.1.</p>
                       </li>
                       <li>
-                        <p>If <var>parsedURL</var>'s [=url/query=] is non-null, run the following
-                        sub-steps and if any of them fail, [=exception/throw=] a "{{SyntaxError}}" {{DOMException}} :</p>
-                        <ol>
-                          <li>Let <var>urlParams</var> be the result of applying <a data-cite="url#concept-urlencoded-string-parser"><code>application/x-www-form-urlencoded</code> string parser</a> to <var>parsedURL</var>'s [=url/query=].</li>
-			  <li>If <var>urlParams</var>’s [=list/size=] is greater than 1, then fail.</li>
-			  <li>If <var>urlParams</var>’s [=list/size=] is 1, let <code>(<var>paramName</var>, <var>paramValue</var>)</code> be the two items of <code><var>urlParams/var>[0]</code>.</li>
-			  <li>If <var>paramName</var> is set and different from <code>"transport"</code>, then fail.</li>
-			  <li>If <var>paramValue</var> is set and different from <code>"udp"</code> or <code>"tcp"</code>, then fail.</li>
+                        <p>If <var>parsedURL</var>'s [=url/query=] is non-null, run the following sub-steps and if any of them fail, [=exception/throw=] a "{{SyntaxError}}" {{DOMException}}:</p>
+			  <ol>
+			    <li>If <var>parsedURL</var>'s [=url/scheme=] is <code>"stun"</code> or <code>"stuns"</code>, then fail.</li>
+			    <li>if <var>parsedURL</var>'s [=url/query=] is different from either <code>"transport=udp"</code> or <code>"transport=tcp"</code>, then fail.</li>
                         </ol>
                       </li>
                       <li>