Fix static type errors in a number of tests

tests/standalone/io/socket_exception_test.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.
 //
 // Tests socket exceptions.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:isolate";
 import "dart:io";
@@ skipping 35 matching lines @@
       });
     });
   }
 
   static void serverSocketListenCloseTest() {
     var port = new ReceivePort();
     ServerSocket.bind().then((server) {
       Socket.connect("127.0.0.1", server.port).then((socket) {
         server.listen(
           (incoming) => server.close(),
-          onDone: port.close());
+          onDone: port.close);
       });
     });
   }
 
   static void clientSocketExceptionTest() {
     bool exceptionCaught = false;
     bool wrongExceptionCaught = false;
 
     ServerSocket.bind().then((server) {
       Expect.isNotNull(server);
@@ skipping 166 matching lines @@
     clientSocketAddCloseErrorTest();
     clientSocketAddCloseResultErrorTest();
     unknownHostTest();
   }
 }
 
 main() {
   SocketExceptionTest.testMain();
 }