Get rid of DART_SDK in pub.

sdk/lib/_internal/pub/test/sdk_test.dart

+// Copyright (c) 2012, 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 pub_tests;
+
+import 'package:unittest/unittest.dart';
+
+import '../lib/src/sdk.dart' as sdk;
+import '../lib/src/version.dart';
+
+main() {
+  group("parseVersion()", () {
+    test("parses a release-style version", () {
+      expect(sdk.parseVersion("0.1.2.0_r17645"),
+          equals(new Version.parse("0.1.2+0.r17645")));
+    });
+
+    test("parses a dev-only style version", () {
+      // The "version" file generated on developer builds is a little funky and
+      // we need to make sure we don't choke on it.
+      expect(sdk.parseVersion("0.1.2.0_r16279_bobross"),
+          equals(new Version.parse("0.1.2+0.r16279.bobross")));
+    });
+  });
+}