Bug: https://bugs.openjdk.java.net/browse/JDK-8130737
Webrev : http://cr.openjdk.java.net/~prr/8130737/
If a child raster is created with a non-zero x-offset then subsequently
in the code that validates the raster for imaging operations we may
incorrectly calculate that the image exceeds the data buffer.
This resolves that and a test has been provided that exercises
each of the code paths with the buggy logic.
This also reorders the arguments to a macro to use width and height
consistently,
and use signed values instead of unsigned in the macros.
-phil.
