- Implement a first cut for const String.env in the VM to allow

tests/corelib/string_env_test.dart

Index: tests/corelib/string_env_test.dart
===================================================================
--- tests/corelib/string_env_test.dart	(revision 0)
+++ tests/corelib/string_env_test.dart	(revision 0)
@@ -0,0 +1,11 @@
+// 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 "package:expect/expect.dart";
+
+main() {
+  Expect.equals("theDefault",
+               const String.env("NOT_IN_ENV", defaultValue:"theDefault"));
+  Expect.equals("", const String.env("NOT_IN_ENV"));
+}