Make isEmpty a getter.

tests/corelib/list_iterators_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.
 
 class ListIteratorsTest {
   static void checkListIterator(List a) {
     Iterator it = a.iterator();
-    Expect.equals(false, it.hasNext == a.isEmpty());
+    Expect.equals(false, it.hasNext == a.isEmpty);
     for (int i = 0; i < a.length; i++) {
       Expect.equals(true, it.hasNext);
       var elem = it.next();
     }
     Expect.equals(false, it.hasNext);
     bool exceptionCaught = false;
     try {
      var eleme = it.next();
     } on NoMoreElementsException catch (e) {
      exceptionCaught = true;
@@ skipping 25 matching lines @@
       // Iterator must realize that g has no more elements.
       g.removeLast();
     }
     Expect.equals(10, sum);
   }
 }
 
 main() {
   ListIteratorsTest.testMain();
 }