Fix tests that were broken in Chrome.

test/utils.dart

Index: test/utils.dart
diff --git a/test/utils.dart b/test/utils.dart
index 0bdeee1297cb1c246b43d053bec1f4320be309b5..b02b5868cbcb58736e12b5082617f239e1754bc0 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -15,6 +15,11 @@ import 'package:unittest/src/runner/load_exception.dart';
 import 'package:unittest/src/util/remote_exception.dart';
 import 'package:unittest/unittest.dart';
 
+/// The string representation of an untyped closure with no arguments.
+///
+/// This differs between dart2js and the VM.
+final String closureString = (() {}).toString();
+
 // The last state change detected via [expectStates].
 State lastState;