Print out experimental test.py reproduction command

tools/testing/dart/test_progress.dart

Index: tools/testing/dart/test_progress.dart
diff --git a/tools/testing/dart/test_progress.dart b/tools/testing/dart/test_progress.dart
index bbe0cbb57a28d3da18b835154bca988c4c3bb001..1447c85b85910c90a3d30b4232d0be675d9a6b25 100644
--- a/tools/testing/dart/test_progress.dart
+++ b/tools/testing/dart/test_progress.dart
@@ -137,6 +137,15 @@ List<String> _buildFailureOutput(TestCase test,
       output.add('Did not run');
     }
   }
+
+  var arguments = ['python', 'tools${Platform.pathSeparator}test.py'];

[ricow1, 2013/06/20 13:54:50]

just write /
python understands that, even on strange operating systems

[kustermann, 2013/06/20 14:17:24]

"even on strange operating system": I like it :-)

+  arguments.addAll(test.configuration['_reproducing_arguments_']);
+  arguments.add(test.displayName);
+  var testPyCommandline = arguments.map(escapeCommandLineArgument).join(' ');
+
+  output.add('');
+  output.add('Short reproduction command (experimental):');
+  output.add("    $testPyCommandline");
   return output;
 }