They don't have any QPA counterpart as they're just plain containers.
This also removes that "Menu does not contain the item to be removed"
warning on Mac.

Task-Number: QTBUG-32197
Change-Id: I06e08817194c2e3ad3efd7ded193bfac9d3a1948
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>