Do not recreate window if it is moved to a virtual sibling screen.

Task-number: QTBUG-32681
Task-number: QTBUG-33062
Change-Id: Id37627231b7a129c398d90d3f01ded6bd5171088
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Ensure the docs for QOpenGLFunctions_ES2 are generated

qdoc runs the preprocessor, so it probably skipped the definition for
this class.

Change-Id: I10933134d0c20131dd25e15bee914ebfac358b10
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Reviewed-by: James Turner <james.turner@kdab.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>