Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/custom/regress_194523002_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for CL 194523002.
+
+library js_custom_test;
+
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'dart:html';
+import '../utils.dart';
+
+class A extends HtmlElement {
+  static final tag = 'x-a';
+  factory A() => new Element.tag(tag);
+  A.created() : super.created();
+}
+
+main() {
+  useHtmlConfiguration();
+
+  // Adapted from Blink's
+  // fast/dom/custom/constructor-calls-created-synchronously test.
+
+  var registered = false;
+  setUp(() {
+    return customElementsReady.then((_) {
+      if (!registered) {
+        registered = true;
+        document.registerElement(A.tag, A);
+      }
+    });
+  });
+}