Read Intl.message examples argument as a map, not a string

pkg/intl/test/message_extraction/make_hardcoded_translation.dart

 #!/usr/bin/env 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.
 
 /**
  * This simulates a translation process, reading the messages generated
  * from extract_message.dart for the files sample_with_messages.dart and
  * part_of_sample_with_messages.dart and writing out hard-coded translations for
  * German and French locales.
@@ skipping 207 matching lines @@
   for (var each in originals) {
     var name = each["name"];
     translated[name] = translations[name];
   }
   var file = new File(path.join(targetDir, 'translation_$locale.json'));
   file.writeAsStringSync(JSON.encode(translated));
 }
 
 main(List<String> args) {
   if (args.length == 0) {
-    print('Usage: generate_hardcoded_translation [--output-dir=<dir>] '
+    print('Usage: make_hardcoded_translation [--output-dir=<dir>] '
         '[originalFile.json]');
     exit(0);
   }
   var parser = new ArgParser();
   parser.addOption("output-dir", defaultsTo: '.',
       callback: (value) => targetDir = value);
   parser.parse(args);
 
   var fileArgs = args.where((x) => x.contains('.json'));
 
   var messages = JSON.decode(new File(fileArgs.first).readAsStringSync());
   translate(messages, "fr", french);
   translate(messages, "de_DE", german);
 }