Move getters from Options to Platform

tests/standalone/io/file_read_stdio_script.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.
 
 import 'dart:io';
 
 void main() {
-  var expected = new File(new Options().script).readAsStringSync();
+  var expected = new File(Platform.script).readAsStringSync();
   var stdin = new File('/dev/fd/0').readAsStringSync();
   if (expected != stdin) {
     throw "stdin not equal expected file";
   }
 }