Make a VM crash more obvious.

dart/tools/test.py

 #!/usr/bin/env python
 # 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.
 
 import os
 import platform
 import string
 import subprocess
 import sys
 
-from utils import GuessOS
+import utils
+
 
 def Main():
   args = sys.argv[1:]
   tools_dir = os.path.dirname(os.path.realpath(__file__))
   dart_binary_prefix = os.path.join(tools_dir, 'testing', 'bin')
-  if GuessOS() == "win32":
+  if utils.IsWindows():
     dart_binary = os.path.join(dart_binary_prefix, 'windows', 'dart.exe')
   else:
-    dart_binary = os.path.join(dart_binary_prefix, GuessOS(), 'dart')
+    dart_binary = os.path.join(dart_binary_prefix, utils.GuessOS(), 'dart')
   current_directory = os.path.abspath('');
   client = os.path.abspath(os.path.join(tools_dir, '..'));
   if current_directory == os.path.join(client, 'runtime'):
     dart_script_name = 'test-runtime.dart'
   elif current_directory == os.path.join(client, 'compiler'):
     dart_script_name = 'test-compiler.dart'
   else:
     dart_script_name = 'test.dart'
   dart_test_script = string.join([tools_dir, dart_script_name], os.sep)
   command = [dart_binary, dart_test_script] + args
-  return subprocess.call(command)
+  exit_code = subprocess.call(command)
+  utils.DiagnoseExitCode(exit_code, command)
+  return exit_code
+
 
 if __name__ == '__main__':
   sys.exit(Main())