Fix test.dart to have the same behavior as test.py for --frog and --froglib.

tools/testing/dart/test_options.dart

 // Copyright (c) 2011, 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.
 
 #library("test_options_parser");
 
 List<String> defaultTestSelectors =
     const ['dartc', 'samples', 'standalone', 'corelib', 'co19', 'language',
            'isolate', 'stub-generator', 'vm', 'client', 'dartdoc'];
 
@@ skipping 140 matching lines @@
               [],
               false,
               'bool'),
           new _TestOptionSpecification(
               'browser',
               'Web browser to use on webdriver tests',
               ['-b', '--browser'],
               ['ff', 'chrome', 'safari', 'ie'],
               'chrome'),
           new _TestOptionSpecification(
-              'flag',
-              'Component-specific extra flags, comma separated',
-              ['--flag'],
+              'frog',
+              'Path to frog executable',
+              ['--frog'],
+              [],
+              ''),
+          new _TestOptionSpecification(
+              'froglib',
+              'Path to frog library',
+              ['--froglib'],
               [],
               '')];
   }
 
 
   /**
    * Parse a list of strings as test options.
    *
    * Returns a list of configurations in which to run the
    * tests. Configurations are maps mapping from option keys to
@@ skipping 291 matching lines @@
         return option;
       }
     }
     print('Unknown test option $name');
     exit(1);
   }
 
 
   List<_TestOptionSpecification> _options;
 }