Remove workaround for showing the TBB's menu bar (Closes #8028).

In the end it seems the TBB will keep on hiding the menu bar, so we
use the menu button instead.
Merge remote-tracking branch 'origin/feature/8028-remove-unsafe-browser-test-menu-workaround' into stable
Merge branch 'stable' into devel
Merge branch 'devel' into experimental