AWT Print Tests: Only include 600dpi tests if requested via main arg '-600dpi'
AWTTilePainter.setupGraphics2DAndClipBounds(): Use 'Shape getClip()'; Use double precicion clip bounds 'all the way'; Explicitly scale image and clip w/ current scaled transform.

- Use 'Shape getClip()'
  Don't assume Rectangle2D, but use Shape's getBounds2D()

- Use double precicion clip bounds 'all the way'
  Remove rounding error on clip bounds w/ start value, which was _not_ using doubles.

- Explicitly scale image and clip w/ current scaled transform.
  Instead of abusing Graphics2D's clip shape to scale image size and clip-area,
  explicitly use transform both bounding boxes into transformed space,
  scale space and transform out (inversion).
  A possible NoninvertibleTransformException will be thrown while Graphics2D has not been modified.