Move getters from Options to Platform

tests/standalone/io/process_pid_test.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.
 //
 // Process test program to test process communication.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
 main() {
   var port = new ReceivePort();
   Expect.isTrue(pid > 0);
   var futures = [];
-  futures.add(Process.start(new Options().executable,['--version']));
-  futures.add(Process.run(new Options().executable,['--version']));
+  futures.add(Process.start(Platform.executable,['--version']));
+  futures.add(Process.run(Platform.executable,['--version']));
   Future.wait(futures).then((results) {
     Expect.isTrue(results[0].pid > 0);
     Expect.isTrue(results[1].pid > 0);
     Expect.equals(0, results[1].exitCode);
     results[0].exitCode.then((exitCode) {
       Expect.equals(0, exitCode);
       port.close();
     });
   });
 }