isolates: remove Isolate2 interface, add top-level spawn functions, more comments

tests/isolate/src/APIv2_spawnStandaloneTest.dart

Index: tests/isolate/src/APIv2_spawnStandaloneTest.dart
diff --git a/tests/isolate/src/APIv2_spawnStandaloneTest.dart b/tests/isolate/src/APIv2_spawnStandaloneTest.dart
index 2d27dc6c85c77071b875e0d803950127220b1644..b118f1b44a97bfd199202eab280d854c6119c906 100644
--- a/tests/isolate/src/APIv2_spawnStandaloneTest.dart
+++ b/tests/isolate/src/APIv2_spawnStandaloneTest.dart
@@ -2,21 +2,21 @@
 // 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.
 
-// example of spawning an isolate from a closure
+// Example of spawning an isolate from a function.
 #library('spawn_tests');
 #import('dart:isolate');
 
-child(ReceivePort port) {
-  port.receive((msg, reply) => reply.send("re: $msg"));
+child() {
+  port.receive((msg, reply) => reply.send('re: $msg'));
 }
 
 main() {
   ReceivePort port = new ReceivePort();
   port.receive((msg, _) {
-    Expect.equals("re: hi", msg);
+    Expect.equals('re: hi', msg);
     port.close();
   });
 
-  Isolate2 c = new Isolate2.fromCode(child);
-  c.sendPort.send("hi", port.toSendPort());
+  SendPort s = spawnFunction(child);
+  s.send('hi', port.toSendPort());
 }