[macosx] setIconImage is not endlessly tolerant to the broken image-arguments

http://java.net/jira/browse/MACOSX_PORT-533 submitted 2011/10/11 by Yuri Nesterenko
Similar XToolkit bug was 6436455.
In this port, if you pass a null image, there's no problem; however if the image e.g. viciously throws an exception from getWidth(ImageObserver), the application fails.
Attaching a regression test and a couple of images (not sure they are needed but add them to the "images" subdir)(frame.ser is a serialized image).