Remove deprecated parts of dart:async.

tests/standalone/io/testing_server.dart

 // Copyright (c) 2013, 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.
 
 part of ServerTest;
 
 abstract class TestingServer {
 
   static const HOST = "127.0.0.1";
   static const INIT = 0;
   static const SHUTDOWN = -1;
 
   void onConnection(Socket connection);  // Abstract.
 
-  void errorHandlerServer(e) {
+  void errorHandlerServer(e, trace) {
     String msg = "Server socket error $e";
-    var trace = getAttachedStackTrace(e);
     if (trace != null) msg += "\nStackTrace: $trace";
     Expect.fail(msg);
   }
 
   SendPort get closeSendPort => _closePort.sendPort;
 
   Future<int> init() {
     _closePort = new ReceivePort();
     _closePort.first.then((_) { close(); });
     return ServerSocket.bind(HOST, 0).then((server) {
       _server = server;
       _server.listen(
           onConnection,
           onError: errorHandlerServer);
       return _server.port;
     });
   }
 
   void close() {
     _server.close();
   }
 
   ServerSocket _server;
   ReceivePort _closePort;
 }