message: [dotest] Remove outdates TODO
  The referenced function `find_test_files_in_dir_tree` no longer exists.
diff: @@ -730,7 +730,6 @@ def visit_file(dir, name):
  unittest2.defaultTestLoader.loadTestsFromName(base))
  -# TODO: This should be replaced with a call to find_test_files_in_dir_tree.
  def visit(prefix, dir, names):
  """Visitor function for os.path.walk(path, visit, arg)."""
  