Implement waitForWindowExposed and friends for widget windows.

Implement waitForWindowExposed and friends for widget windows.

- Implement waitForWindowExposed() for toplevel windows.
- Implement waitForWindowShown(QWidget *) and mark as
  deprecated in line with waitForWindowShown(QWindow*).
- Use in tests.
- Simplify tests (collapse waitForExposed, setActive
  into setActiveWindow, waitForActive), remove most
  hard-coded timeouts.
- Stabilize graphicsview tests by using waitForWindowActive.

Change-Id: Ic7c061e2745b36f71a715ee4e47c0346b11a91e8
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>