tst_QGraphicsEffect::prepareGeometryChangeInvalidateCache is flaky on openSUSE

 agent:2018/09/18 12:37:47 build.go:193: FAIL!  : tst_QGraphicsEffect::prepareGeometryChangeInvalidateCache() Compared values are not the same
agent:2018/09/18 12:37:47 build.go:193:    Actual   (item->nbPaint): 1
agent:2018/09/18 12:37:47 build.go:193:    Expected (0)            : 0
agent:2018/09/18 12:37:47 build.go:193:    Loc: [tst_qgraphicseffect.cpp(711)]