Windows don't allow insecure guest login anymore by default. It need
to be enabled through Group Policy restrictions
Pick-to: 5.15
Pick-to: 5.12
Task-number: QTQAINFRA-3980
Change-Id: I767e9c87ca3ee4737e312142ecefb94ee2b2b828
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>