Temporarily pin qtbase similar to qtdeclarative

Change-Id: I95b101670fd4f767d311ea015d0836f6d09931aa
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Fix tst_applicationwindow::test_minimumHeight()

QQuickWindow::contentItem is now resized in resizeEvent() so
the window must be visible if a test relies on content item's
size.

Change-Id: If354306d80bd2fcf47114d726fa5987c60399b2e
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@digia.com>