test(change detector): re-add a previously failing test

Author: vicb

test/change_detection/dirty_checking_change_detector_spec.dart

@@ -294,12 +294,11 @@ main() => describe('DirtyCheckingChangeDetector', () {
       detector.collectChanges();
       list.insert(0, 'b');
       expect(list).toEqual(['b', 'a', 'a', 'b', 'b']);
-      // todo(vbe) There is something wrong when running this test w/ karma
-//      expect(detector.collectChanges().currentValue, toEqualCollectionRecord(
-//          collection: ['b[2 -> 0]', 'a[0 -> 1]', 'a[1 -> 2]', 'b', 'b[null -> 4]'],
-//          additions: ['b[null -> 4]'],
-//          moves: ['b[2 -> 0]', 'a[0 -> 1]', 'a[1 -> 2]'],
-//          removals: []));
+      expect(detector.collectChanges().currentValue, toEqualCollectionRecord(
+          collection: ['b[2 -> 0]', 'a[0 -> 1]', 'a[1 -> 2]', 'b', 'b[null -> 4]'],
+          additions: ['b[null -> 4]'],
+          moves: ['b[2 -> 0]', 'a[0 -> 1]', 'a[1 -> 2]'],
+          removals: []));
     });
 
     it('should support UnmodifiableListView', () {