mojob.py: add nacltest command.

mojo/tools/mojob.py

Index: mojo/tools/mojob.py
diff --git a/mojo/tools/mojob.py b/mojo/tools/mojob.py
index 5bb57edec8c235d31b20866c656b543dc1c4744c..3461ec4d67e3d93c093553141776e84ac46aecb4 100755
--- a/mojo/tools/mojob.py
+++ b/mojo/tools/mojob.py
@@ -195,6 +195,10 @@ def darttest(config):
   return _run_tests(config, ['dart'])
 
 
+def nacltest(config):
+  return _run_tests(config, ['nacl'])
+
+
 def main():
   os.chdir(Paths().src_root)
 
@@ -283,6 +287,10 @@ def main():
       help='Run Dart unit tests (does not build).')
   darttest_parser.set_defaults(func=darttest)
 
+  nacltest_parser = subparsers.add_parser('nacltest', parents=[parent_parser],
+      help='Run NaCl unit tests (does not build).')
+  nacltest_parser.set_defaults(func=nacltest)
+
   args = parser.parse_args()
   config = _args_to_config(args)
   return args.func(config)