Make isEmpty a getter.

tests/corelib/reg_exp_all_matches_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.
 
 // Dart test program for RegExp.allMatches.
 
 class RegExpAllMatchesTest {
   static testIterator() {
     var matches = new RegExp("foo").allMatches("foo foo");
     Iterator it = matches.iterator();
@@ skipping 69 matching lines @@
     Expect.equals(true, matches.some((Match m) {
       return m.group(0).startsWith("foo");
     }));
     Expect.equals(false, matches.some((Match m) {
       return m.group(0).startsWith("fooo");
     }));
   }
 
   static testIsEmpty() {
     var matches = new RegExp("foo?").allMatches("foo fo foo fo");
-    Expect.equals(false, matches.isEmpty());
+    Expect.equals(false, matches.isEmpty);
     matches = new RegExp("fooo").allMatches("foo fo foo fo");
-    Expect.equals(true, matches.isEmpty());
+    Expect.equals(true, matches.isEmpty);
   }
 
   static testGetCount() {
     var matches = new RegExp("foo?").allMatches("foo fo foo fo");
     Expect.equals(4, matches.length);
     matches = new RegExp("fooo").allMatches("foo fo foo fo");
     Expect.equals(0, matches.length);
   }
 
   static testMain() {
     testIterator();
     testForEach();
     testMap();
     testFilter();
     testEvery();
     testSome();
     testIsEmpty();
     testGetCount();
   }
 }
 
 main() {
   RegExpAllMatchesTest.testMain();
 }