QPrintSupport: Move QAbstractPrintDialog test into QPrintSupport

Move the test for QAbstractPrintDialog from widgets into printsupport

Change-Id: Ia7595fa650a7ad565df3090207500ed06564e842
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Add empty dist/changes-5.3.0 file

Change-Id: Iea2f6bb3b1d5c922167c4e96c825c08db9aa1b4e
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>