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

tests/standalone/io/echo_server_test.dart

Index: tests/standalone/io/echo_server_test.dart
diff --git a/tests/standalone/io/echo_server_test.dart b/tests/standalone/io/echo_server_test.dart
index d197369799fe25787be5eef312237b0f3bdbe700..6d5a7cff2adf86c69a3a307427ebf6ddb5e78fcb 100644
--- a/tests/standalone/io/echo_server_test.dart
+++ b/tests/standalone/io/echo_server_test.dart
@@ -35,10 +35,8 @@ class EchoServerGame {
     for (int i = 0; i < MSGSIZE; i++) {
       _buffer[i] = FIRSTCHAR + i;
     }
-    new EchoServer().spawn().then((SendPort port) {
-      _sendPort = port;
-      start();
-    });
+    _sendPort = spawnFunction(startEchoServer);
+    start();
   }
 
   void sendData() {
@@ -129,6 +127,14 @@ class EchoServerGame {
   int _messages;
 }
 
+
+void startEchoServer() {
+  var server = new EchoServer();
+  port.receive((message, replyTo) {
+    server.dispatch(message, replyTo);
+  });
+}
+
 class EchoServer extends TestingServer {
 
   static final msgSize = EchoServerGame.MSGSIZE;