These tests contains fixed timeouts which sometimes is not enough,
causing the test to fail under heavy load.
Since isFinished() doesn't actually tell if a device has started,
the timeout might come too early, e.g., when the device is still waiting
for data, or even before it has started.

Change-Id: I8f2f8341b9fcf656d86d161203c7eb63e66acca5
Reviewed-by: Christian Stromme <christian.stromme@qt.io>