When tearing off either a non-scrollable multi-colume menu
or a scrollable menu, displaying the torn-off menu crashes.
The root cause is when the torn-off menu is created, the
tear-off menu's style, margins and other attributes are not
set to it. The patch is to ensure the torn-off menu has
the same attributes as the tear-off menu does and set the
torn-off menu with a correct menu size.
Task-number: QTBUG-24815
Change-Id: Icea45f149ea8792671af4a62e62cad6ee01a1f95
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>
ae6ef2e3ec