Add flag to tools/test.dart. Add utils test suite to list of default suites.

tools/testing/dart/test_suite.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_suite");
 
 #import("dart:io");
 #import("status_file_parser.dart");
 #import("test_runner.dart");
 #import("multitest.dart");
@@ skipping 568 matching lines @@
         return null;
     }
   }
 
   String getHtmlName(String filename) {
     return filename.replaceAll('/', '_').replaceAll(':', '_') 
         + configuration['component'] + '.html';
   }
 
   String get dumpRenderTreeFilename() {
+    if (configuration['drt'] != '') {
+      return configuration['drt'];
+    }
     if (new Platform().operatingSystem() == 'macos') {
       return 'client/tests/drt/DumpRenderTree.app/Contents/' +
           'MacOS/DumpRenderTree';
     }
     return 'client/tests/drt/DumpRenderTree';
   }
 
   void testGeneratorStarted() {
     ++activeTestGenerators;
   }
@@ skipping 461 matching lines @@
  * $noCrash tests are expected to be flaky but not crash
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
 """;
     print(report);
    }
 }