Menus do not expand on access denied pages

For instance, a user can have permissions to create several content types, which would normally be listed under "Add new content" when this link is set to expand. If the user navigates to a page where he does not have access, such as a different content type node/add form, "Add new content" is not expanded an this context is denied him.

Steps to recreate:
* Edit a menu item that has children (admin/structure/menu/item/17/edit) and mark it as "Show as expanded".
* Visit user/register (when logged in) or another page to which one does not have access.
* Observe the menu in question, such as the Management menu.

(A bigger, related usability issue is the disappearance of primary links on "Page not found" errors, but that appears to be a different issue entirely: #233807: No navigation links on 404 pages)