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

tests/isolate/nested_spawn_test.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 // Dart test program for testing that isolates can spawn other isolates.
 
 #library('NestedSpawnTest');
 #import("dart:isolate");
 #import('../../lib/unittest/unittest.dart');
 
-class IsolateA extends Isolate {
-  IsolateA() : super.heavy();
-
-  void main() {
-    this.port.receive((msg, replyTo) {
-      Expect.equals("launch nested!", msg);
-      new IsolateB().spawn().then((SendPort p) {
-        p.call("alive?").then((msg) {
-          Expect.equals("and kicking", msg);
-          replyTo.send(499, null);
-          this.port.close();
-        });
-      });
+void isolateA() {
+  port.receive((msg, replyTo) {
+    Expect.equals("launch nested!", msg);
+    SendPort p = spawnFunction(isolateB);
+    p.call("alive?").then((msg) {
+      Expect.equals("and kicking", msg);
+      replyTo.send(499, null);
+      port.close();
     });
-  }
+  });
 }
 
-class IsolateB extends Isolate {
-  IsolateB() : super.heavy();
-
-  void main() {
-    this.port.receive((msg, replyTo) {
-      Expect.equals("alive?", msg);
-      replyTo.send("and kicking", null);
-      this.port.close();
-    });
-  }
+void isolateB() {
+  port.receive((msg, replyTo) {
+    Expect.equals("alive?", msg);
+    replyTo.send("and kicking", null);
+    port.close();
+  });
 }
 
 
 main() {
   test("spawned isolates can spawn nested isolates", () {
-    new IsolateA().spawn().then(expectAsync1((SendPort port) {
-      port.call("launch nested!").then(expectAsync1((msg) {
-        Expect.equals(499, msg);
-      }));
+    SendPort port = spawnFunction(isolateA);
+    port.call("launch nested!").then(expectAsync1((msg) {
+      Expect.equals(499, msg);
     }));
   });
 }