In the TestBook2.odt of fdo#73300 it happens that at some particular
points when scrolling down, the
ViewObjectContactOfPageHierarchy::getPrimitive2DSequenceHierarchy()
will determine that > 200 images are visible; most likely this is due to
an empty ObjectContactOfPageView::maViewInformation2D::getViewport().

Loading this many images may need more RAM than is available on 32bit
platforms.

That appears to happen only (but not always) if somehow (not sure
how exactly) the rectangle passed to SdrPageView::DrawLayer() and the
existing GetRedrawRegion() do not overlap at all.

(regression from commit 8af09bf3)

Change-Id: Iafc595241df05204bccec1f2336014fc471b6602