Hangs on huge `node_modules`

I love this module but unfortunately I can not use it, `worktree.Status()` hangs because tree is trimmed from ignored files only [after](https://github.com/src-d/go-git/blob/e4ce8aacbcfc2ba341b6dc1938cd16deb734fe56/worktree_status.go#L132).

In my opinion same reason or related: #636 