Add mirrors tests

test/codegen/lib/mirrors/closure_mirror_import1.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.
+
+library closure_mirror_import1;
+
+export "closure_mirror_import2.dart" show firstGlobalVariableInImport2;
+
+var globalVariableInImport1 = "globalVariableInImport1";
+
+globalFunctionInImport1() => "globalFunctionInImport1";
+
+class StaticClass {
+  static var staticField = "staticField";
+
+  static staticFunctionInStaticClass() => "staticFunctionInStaticClass";
+}