After the recent refactoring in 28b14b966f
this test should run stable on all platforms. However, the way the test
was written made it quite flaky. Simplify it to verify that closing one
window doesn't prevent a second timer to fire (which it would if closing
the first window already quit the application).
Change-Id: I0306792cd7573ebd3418d1aabffe2b78700ec2d9
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
6dc587dfdd