The previous code would only invoke Window:: methods by the time we
hit the destructor; do the same to avoid fixing more scattered
crashers for now.

Reviewed-on: https://gerrit.libreoffice.org/15880Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

Conflicts:
	vcl/source/control/slider.cxx

Change-Id: Ibdcd1290309bb7fc31a44d534c52d357da022591