Change quoting in Process implementation on Windows.

tests/standalone/src/io/ProcessCheckArgumentsScript.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.
+//
+// Utility script to check that arguments are correctly passed from
+// one dart process to another using the dart:io process interface.
+
+main() {
+  var options = new Options();
+  Expect.isTrue(options.script.endsWith('ProcessCheckArgumentsScript.dart'));
+  var expected_num_args = Math.parseInt(options.arguments[0]);
+  Expect.equals(expected_num_args, options.arguments.length);
+  for (var i = 0; i < options.arguments.length; i++) {
+    Expect.isFalse(options.arguments[i].contains('"'));
+  }
+}