Fix static type errors in a number of tests

tests/standalone/io/socket_close_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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 //
 // Test socket close events.
@@ skipping 72 matching lines @@
           proceed();
           break;
         case 6:
           proceed();
           break;
         default:
           Expect.fail("Unknown test mode");
       }
     }
 
-    void errorHandler(Exception e) {
+    void errorHandler(Socket socket) {
       _errorEvents++;
       socket.close();
     }
 
     void connectHandler(socket) {
       socket.listen(
           dataHandler,
           onDone: () => closeHandler(socket),
           onError: (error) => errorHandler(socket));
 
@@ skipping 274 matching lines @@
   var tests = 7;
   var port = new ReceivePort();
   var completed = 0;
   port.receive((message, ignore) {
     if (++completed == tests) port.close();
   });
   for (var i = 0; i < tests; i++) {
     new SocketClose.start(i, port.toSendPort());
   }
 }