use .append instead of .nodes.add

tests/html/js_interop_2_test.dart

 // Copyright (c) 2012, 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
 
 library JsInterop2Test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 import 'dart:isolate';
 
 injectSource(code) {
   final script = new ScriptElement();
   script.type = 'text/javascript';
   script.innerHtml = code;
-  document.body.nodes.add(script);
+  document.body.append(script);
 }
 
 var isolateTest = """
   function test(data) {
     if (data == 'sent')
       return 'received';
   }
 
   var port = new ReceivePortSync();
   port.receive(test);
@@ skipping 28 matching lines @@
     injectSource(portEqualityTest);
 
     SendPortSync port1 = window.lookupPort('identity');
     SendPortSync port2 = window.lookupPort('identity');
     expect(port1, equals(port2));
 
     SendPortSync port3 = port1.callSync(port2);
     expect(port3, equals(port2));
   });
 }