Fix #536: abort document.open() if origins mismatch

This matches the implementation of Firefox, and will automatically
resolve the issue that we use the document's origin for initializing the
realm but the responsible document's url for setting the url: After this
change, the document's origin and the responsible document's origin will
be equal.

source

@@ -86991,6 +86991,11 @@ interface <dfn>WindowBase64</dfn> {
    <li><p>If the <code>Document</code> object is not an <span>active document</span>, then abort
    these steps.</p></li>
 
+   <li><p>If the <span>origin</span> of the <code>Document</code> is not equal to the
+   <span>origin</span> of the <span>responsible document</span> specified by the <span>entry
+   settings object</span>, throw a <code>SecurityError</code> exception and abort these
+   steps.</p></li>
+
    <li><p>Let <var>type</var> be the value of the first argument.</p></li>
 
    <li>
@@ -116929,6 +116934,7 @@ INSERT INTERFACES HERE
   Jirka Kosek,
   Jjgod Jiang,
   Jo&atilde;o Eiras,
+  Jochen Eisinger,
   Joe Clark,
   Joe Gregorio,
   Joel Spolsky,