use .append instead of .nodes.add

tests/html/js_interop_3_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 JsInterop3Test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:async';
 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 jsToDart = """
   var fun1 = window.lookupPort('fun1');
   var result = fun1.callSync({'a': 'Hello', 'b': 'World', c: 42});
 
   var fun2 = window.lookupPort('fun2');
   fun2.callSync(result);
 """;
 
@@ skipping 20 matching lines @@
       Timer.run(done);
     };
 
     var port2 = new ReceivePortSync();
     port2.receive(fun2);
     window.registerPort('fun2', port2.toSendPort());
 
     injectSource(jsToDart);
   });
 }