- Replace by qWaitForWindowExposed() or
  qWaitForWindowActive() where applicable.
- Use QVERIFY to verify success.
- Stabilize some tests by checking for 'active',
  add missing call to show().

Change-Id: I6cae063e44a3839760ed9f61dacb26cd1717118d
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>