Allow Platform.executable for JIT app snapshots.

tests/standalone/io/process_detached_test.dart

 // Copyright (c) 2015, 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.
-//
+
+// OtherResources=process_detached_script.dart
+
 // Process test program to test detached processes.
 
 import 'dart:async';
 import 'dart:io';
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 
 import "process_test_util.dart";
 
@@ skipping 60 matching lines @@
       asyncEnd();
     });
   });
 }
 
 main() {
   test();
   testWithStdio();
   testFailure();
 }