Change core lib, dart2js, and more for new optional parameters syntax

tests/standalone/io/echo_server_stream_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.
 //
 // Echo server test program to test socket streams.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
@@ skipping 77 matching lines @@
           stream.write(_buffer);
           break;
         case 1:
           stream.write(_buffer, false);
           break;
         case 2:
           stream.writeFrom(_buffer);
           break;
         case 3:
           Expect.equals(0, _buffer.length % 2);
-          stream.writeFrom(_buffer, len: _buffer.length ~/ 2);
+          stream.writeFrom(_buffer, 0, _buffer.length ~/ 2);
           stream.writeFrom(_buffer, _buffer.length ~/ 2);
           break;
       }
       stream.close();
       dataSent();
     }
 
     _socket = new Socket(TestingServer.HOST, _port);
     if (_socket !== null) {
       _socket.onConnect = connectHandler;
@@ skipping 62 matching lines @@
 
     inputStream = connection.inputStream;
     inputStream.onData = dataReceived;
     connection.onError = errorHandler;
   }
 }
 
 main() {
   EchoServerGame echoServerGame = new EchoServerGame.start();
 }