fdo#74424 Use Window::GetOutDev() to access ImplReMirrored()

Part of the decoupling of Window from OutputDevice. We now get
he Window's OutputDevice instance and manipulate this. Do not rely
on the inherited function.

Conflicts:
	include/vcl/window.hxx

Change-Id: Ie422df837e1596881b61d34a1627b0ecc668a54e
Reviewed-on: https://gerrit.libreoffice.org/7793
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>