Fix typo in set_test.dart, makes analyzer complain.

tests/corelib/set_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.
 
 library set_test;
 
 
 import 'package:expect/expect.dart';
 import "dart:collection";
 
@@ skipping 415 matching lines @@
   Expect.isTrue(set4.isEmpty);
 }
 
 void testCESetFrom(setFrom) {
   List<Object> ceList = [new CE(2), new CE(3), new CE(5),
                          new CE(7), new CE(11), new CE(13)];
 
   Set<CE> set1 = setFrom(ceList);
   Expect.listEquals(ceList, set1.toList()..sort());
 
-  Set<ce> ceSet = ceList.toSet();
+  Set<CE> ceSet = ceList.toSet();
   Set<CE> set2 = setFrom(ceSet);
   Expect.listEquals(ceList, set2.toList()..sort());
 
-  Iterable<ce> ceIter = ceList.where((x) => true);
+  Iterable<CE> ceIter = ceList.where((x) => true);
   Set<CE> set3 = setFrom(ceIter);
   Expect.listEquals(ceList, set3.toList()..sort());
 
   Set<CE> set4 = setFrom(new Iterable.generate(0));
   Expect.isTrue(set4.isEmpty);
 }
 
 main() {
   testMain(() => new HashSet());
   testMain(() => new LinkedHashSet());
@@ skipping 51 matching lines @@
 
   testCESetFrom((x) => new Set<CE>.from(x));
   testCESetFrom((x) => new HashSet<CE>.from(x));
   testCESetFrom((x) => new LinkedHashSet<CE>.from(x));
   testCESetFrom((x) => new SplayTreeSet<CE>.from(x));
 
   testCESetFrom((x) => new SplayTreeSet<CE>.from(x,
                                                  customCompare(20), validKey));
   testCESetFrom((x) => new SplayTreeSet<CE>.from(x, identityCompare));
 }