Create package for incremental compilation.

dart/tests/compiler/dart2js/incremental/incremental_helper.dart

Index: dart/tests/compiler/dart2js/incremental/incremental_helper.dart
diff --git a/dart/tests/compiler/dart2js/incremental/incremental_helper.dart b/dart/tests/compiler/dart2js/incremental/incremental_helper.dart
deleted file mode 100644
index 3bdf8e3805871396bb29a913d3efa7ca5b4153f1..0000000000000000000000000000000000000000
--- a/dart/tests/compiler/dart2js/incremental/incremental_helper.dart
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright (c) 2014, 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.
-
-const List<String> INCREMENTAL_OPTIONS = const <String>[
-    '--analyze-main',
-    '--disable-type-inference',
-    '--incremental-support',
-    '--no-source-maps',
-];