Adding package:smoke. This CL includes the intial APIs, a mirror-based

pkg/smoke/test/mirrors_test.dart

Index: pkg/smoke/test/mirrors_test.dart
diff --git a/tests/language/regress_16640_test.dart b/pkg/smoke/test/mirrors_test.dart
similarity index 54%
copy from tests/language/regress_16640_test.dart
copy to pkg/smoke/test/mirrors_test.dart
index 64d8654282fa37f9f44f6312ac5ba452f07a18e0..cac643aab81c93a6e746f0e98bda711882f6c7f6 100644
--- a/tests/language/regress_16640_test.dart
+++ b/pkg/smoke/test/mirrors_test.dart
@@ -2,14 +2,13 @@
 // 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.
 
-// Regression test for issue 16640.
+library smoke.test.mirrors_test;
 
-class Segment extends SegmentGen { }
-
-class SegmentGen extends ConceptEntity<Segment> { }
-
-class ConceptEntity<E> { }
+import 'package:smoke/mirrors.dart';
+import 'package:unittest/unittest.dart';
+import 'common.dart' as common show main;
 
 main() {
-  new ConceptEntity<Segment>();
+  setUp(useMirrors);
+  common.main();
 }