Reduce usage of Q_ASSERT in autotests.

Reduce usage of Q_ASSERT in autotests.

Using Q_ASSERT does nothing in release-mode builds, and in debug builds
it causes tests to terminate prematurely.  It is much better to use
QVERIFY or QCOMPARE.

Task-number: QTBUG-17582
Reviewed-by: Rohan McGovern
(cherry picked from commit 3475168550c1a804f04f2a4edfeb30c04cd36551)

Change-Id: Ic39972b685ca35a9a71d9c8d03e8dae31481fb19