Use command on Windows that ends quickly.

tests/standalone/io/process_path_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.
 //
 // Test that the executable is looked up on the user's PATH when spawning a
 // process.
 
 #import('dart:io');
 
 main() {
   // Pick an app that we expect to be on the PATH that returns 0 when run with
   // no arguments.
-  var executable = Platform.operatingSystem == 'windows' ? 'cmd.exe' : 'true';
+  var executable = 'true';
+  var args = [];
+  if (Platform.operatingSystem == 'windows') {
+    executable = 'cmd.exe';
+    args = ['/C', 'echo', '"ok"'];
+  }
 
   var options = new ProcessOptions();
-  Process.run(executable, []).then((result) {
+  Process.run(executable, args).then((result) {
     Expect.equals(0, result.exitCode);
   });
 }