Fix up and un-skip the test for bug 406572, following up on a comment in bug 577325. r=jorendorff

--HG--
rename : content/canvas/test/test_toBlob.html => content/canvas/test/test_mozGetAsFile.html
extra : rebase_source : 8457c42ff9ba9151f240462e06192fa4dc444a75

js/src/tests/js1_5/extensions/regress-406572.js

@@ -1,4 +1,3 @@
-// |reftest| skip
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -15,25 +14,19 @@ printStatus (summary);
 
 if (typeof window != 'undefined')
 {
-  try
-  {
-    expect = 'TypeError: redeclaration of const document';
-    var d = document;
+  var d = document;
 
-    d.writeln(uneval(document));
-    document = 1;
-    d.writeln(uneval(document));
+  d.writeln(uneval(document));
+  document = 1;
+  d.writeln(uneval(document));
 
-    if (1) 
-      function document() { return 1; }
+  if (1)
+    function document() { return 1; }
 
-    d.writeln(uneval(document));
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-    print(actual);
-  }
+  d.writeln(uneval(document));
+
+  // The test harness relies on document having its original value: restore it.
+  document = d;
 }
 else
 {