Make hashCode a getter and not a method.

tests/isolate/port_test.dart

 // Copyright (c) 2011, 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.
 
 // Test properties of ports.
 // Note: unittest.dart depends on ports, in particular on the behaviour tested
 // here. To keep things simple, we don't use the unittest library here.
 
 #library("PortTest");
 #import("dart:isolate");
 
 
 main() {
   testHashCode();
   testEquals();
   testMap();
 }
 
 void testHashCode() {
   ReceivePort rp0 = new ReceivePort();
   ReceivePort rp1 = new ReceivePort();
-  Expect.equals(rp0.toSendPort().hashCode(), rp0.toSendPort().hashCode());
-  Expect.equals(rp1.toSendPort().hashCode(), rp1.toSendPort().hashCode());
+  Expect.equals(rp0.toSendPort().hashCode, rp0.toSendPort().hashCode);
+  Expect.equals(rp1.toSendPort().hashCode, rp1.toSendPort().hashCode);
   rp0.close();
   rp1.close();
 }
 
 void testEquals() {
   ReceivePort rp0 = new ReceivePort();
   ReceivePort rp1 = new ReceivePort();
   Expect.equals(rp0.toSendPort(), rp0.toSendPort());
   Expect.equals(rp1.toSendPort(), rp1.toSendPort());
   Expect.equals(false, (rp0.toSendPort() == rp1.toSendPort()));
@@ skipping 18 matching lines @@
   Expect.equals(false, map.containsKey(rp0.toSendPort()));
   Expect.equals(87, map[rp1.toSendPort()]);
 
   map.remove(rp1.toSendPort());
   Expect.equals(false, map.containsKey(rp0.toSendPort()));
   Expect.equals(false, map.containsKey(rp1.toSendPort()));
 
   rp0.close();
   rp1.close();
 }