trivial: Fix up the tests for CdTransform

The width and height were swapped, which for most of the time doesn't matter.
When the image is stored planar, it really matters.
Correctly convert all of the image when using CdTransform

We were not advancing the memory location by a multiple of the bytes-per-pixel,
which meant we processed the right amount of data, but never wrote out the 3/4
of the image for a RGB32 type.