Add mirrors tests

test/codegen/lib/mirrors/closures_test.dart

+// Copyright (c) 2013, 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.
+
+import 'dart:mirrors';
+import 'package:expect/expect.dart';
+import 'stringify.dart';
+
+testIntercepted() {
+  var instance = [];
+  var closureMirror = reflect(instance.toString);
+  var methodMirror = closureMirror.function;
+  Expect.equals(#toString, methodMirror.simpleName);
+  Expect.equals('[]', closureMirror.apply([]).reflectee);
+}
+
+testNonIntercepted() {
+  var closure = new Map().containsKey;
+  var closureMirror = reflect(closure);
+  var methodMirror = closureMirror.function;
+  Expect.equals(#containsKey, methodMirror.simpleName);
+  Expect.isFalse(closureMirror.apply([7]).reflectee);
+}
+
+main() {
+  testIntercepted();
+  testNonIntercepted();
+}