Change TestEvent key default event routing behavior

Change TestEvent key default event routing behavior

The current behavior of the TestEvent is to send all the
key events to the test window. For this reason is not possible routing
events to custom windows created inside the test suite.
The new behavior is to send the key events to the current focused window

[Change][QuickTest][TestCase]
Changed default routing behavior for key events in TestCase.
The key events are sent to the window with active focus

Change-Id: I6ff3113eb9f1cbc25f6cfd2dd7bfdff178ee6ac3
Reviewed-by: Filippo Cucchetto <filippocucchetto@gmail.com>
Reviewed-by: Mitch Curtis <mitch.curtis@theqtcompany.com>