Improve handling of intentionally broken links in test scripts.

tests/html/audioelement_test.dart

Index: tests/html/audioelement_test.dart
diff --git a/tests/html/audioelement_test.dart b/tests/html/audioelement_test.dart
index 28285962f8404875446df8c8e271f4374b114ce3..02c89359bb1ae9a9c78e2618888194978fa1b4fc 100644
--- a/tests/html/audioelement_test.dart
+++ b/tests/html/audioelement_test.dart
@@ -13,9 +13,9 @@ main() {
     });
 
   test('constructorTest2', () {
-      var audio = new AudioElement('hahaURL');
+      var audio = new AudioElement('IntentionallyMissingFileURL');
       expect(audio, isNotNull);
       expect(audio is AudioElement, isTrue);
-      expect(audio.src, contains('hahaURL'));
+      expect(audio.src, contains('IntentionallyMissingFileURL'));
     });
 }