Configuration translation only works with Stark

Problem/Motivation

After installing D8 using standard profile, using Seven or Bartik theme, all config translation pages are broken, giving a fatal PHP error, eg:
admin/structure/types/manage/article/fields/node.article.body/translate
admin/config/user-interface/shortcut/manage/default/translate
and so on.

The error:

PHP Fatal error:  Call to a member function getBodyAttributes() on a non-object in //d8/core/themes/seven/seven.theme on line 39, referer: http://d8.local/admin/config/user-interface/shortcut                                                                                 

It works only with the theme what's using for testing: Stark.

Proposed resolution

Debug the reason and fix it.

User interface changes

None. It should work/look the same.

API changes

No API change.