To increase the effective test coverage, this patch
re-enables the tst_qgraphicswidget test case as such, and
instead disables only the test functions that are currently
failing in CI.
Task-number: QTBUG-22453
Change-Id: Ic484fde3492f077453f47a959dd6dc862288dcaf
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>