Whenever someone creates a connection to any of the global transform releated
properties for a QQuick3DNode, we inform the scene manager about it. What it
means is that we need to calulate the global transform and emit changes to it
whenever it changes. But knowing when it changes is costly, since it will change
whenever the transform of an ancestor change (and we don't want to listen for
that all the way to the root). So the scene manager will instead delay all global
transform calculations to a be done in a single pass before we update instead.