Remove old isolate API and update all code in the repository to use

tests/html/js_interop_4_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('JsInterop4Test');
 #import('../../lib/unittest/unittest.dart');
 #import('../../lib/unittest/html_config.dart');
 #import('dart:html');
 #import('dart:isolate');
 
 final testData = const [1, '2', 'true'];
 
-// TODO(vsm): Convert all DOM isolate tests to the new syntax.
-class TestIsolate extends Isolate {
-  TestIsolate() : super();
+void testIsolateEntry() {
+  var fun1 = window.lookupPort('fun1');
+  var result = fun1.callSync(testData);
 
-  void main() {
-    var fun1 = window.lookupPort('fun1');
-    var result = fun1.callSync(testData);
-
-    var fun2 = window.lookupPort('fun2');
-    fun2.callSync(result);
-  }
+  var fun2 = window.lookupPort('fun2');
+  fun2.callSync(result);
 }
 
 main() {
   useHtmlConfiguration();
 
   // Test that our interop scheme also works from Dart to Dart.
   test('dart-to-dart-same-isolate', () {
     var fun = expectAsync1((message) {
       Expect.listEquals(testData, message);
       return message.length;
@@ skipping 23 matching lines @@
     var done = expectAsync0(() {});
     var fun2 = (message) {
       Expect.equals(3, message);
       window.setTimeout(done, 0);
     };
 
     var port2 = new ReceivePortSync();
     port2.receive(fun2);
     window.registerPort('fun2', port2.toSendPort());
 
-    new TestIsolate().spawn();
+    spawnFunction(testIsolateEntry);
   });
 }