Move Options to dart:io.

tests/compiler/dart2js/mini_parser_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.
 
 // Simple test to ensure that mini_parser keeps working.
 
+import 'dart:io';
 import '../../../sdk/lib/_internal/compiler/implementation/tools/mini_parser.dart'
     as tool;
 
 void main() {
   // Parse this script itself.
   tool.toolMain(<String>[ new Options().script ]);
 }
 
 /** This class is unused but used to test mini_parser.dart. */
 class TestClass {
   foo() {}
   var i;
 }