Remove QTRY_ macro from tst_qabstractitemview.

Change-Id: Ic8b8e5c242b640581aa735a3716666d4e7ff44eb
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Don't accept wheel events if sendEvent() returns false.

Otherwise wheeling over disabled items won't let the wheel event
propagate to the parent.

An easy way to reproduce the problem is by having a flickable with
some disabled item in it.

Task-number: QTBUG-33477
Change-Id: Ib327cc34dd9f415617ffbc41064f689507446c05
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>