Adding isNotEmpty property to collection and string.

tests/corelib/core_runtime_types_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.
 
 import "package:expect/expect.dart";
 
 /**
  * A test of simple runtime behavior on numbers, strings and lists with
  * a focus on both correct behavior and runtime errors.
  *
@@ skipping 149 matching lines @@
     assertEquals(s.length, 6);
     assertTypeError(() { s[null]; });
     assertTypeError(() { s['hello']; });
     assertTypeError(() { s[0] = 'x'; });
   }
 
   // TODO(jimhug): Fill out full set of string methods.
   static testStringMethods() {
     var s = "abcdef";
     assertEquals(s.isEmpty, false);
+    assertEquals(s.isNotEmpty, true);
     assertEquals(s.startsWith("abc"), true);
     assertEquals(s.endsWith("def"), true);
     assertEquals(s.startsWith("aa"), false);
     assertEquals(s.endsWith("ff"), false);
     assertEquals(s.contains('cd', 0), true);
     assertEquals(s.contains('cd', 2), true);
     assertEquals(s.contains('cd', 3), false);
     assertEquals(s.indexOf('cd', 2), 2);
     assertEquals(s.indexOf('cd', 3), -1);
 
@@ skipping 96 matching lines @@
     '${true}'.toString();
     '${false}'.toString();
     ''.toString();
     ''.endsWith('');
   }
 }
 
 main() {
   CoreRuntimeTypesTest.testMain();
 }