THREENode.rasterized resolution doesn't scale properly

[Denz1994]

Found during phetsims/build-a-molecule#139:

An IconNode is created in BAM/Molecule3DDialog.js with a pattern as follows
const iconNode = ThreeNode.rasterized({resolution:2});The iconNode is then added to an aquaRadioButton. The appearance looks as though the aquaRadioButton.node is scaled-down but its scale isn't restored so the icon looks tiny.

@jonathanolson Mentioned that this may be a problem with the THREENode scaling handled in Node.rasterized(). @jonathanolson asked to be assigned to investigate.