The CL_UNORM_SHORT_555 and CL_UNORM_INT_101010 formats contain padding
bits which need to be ignored in clCopyImage and clFillImage testing.
For clFillImage tests, padding was not ignored for the CL_UNORM_SHORT_555
format, and was ignored for CL_UNORM_INT_101010 by modifying actual and
reference data. For clCopyImage tests, padding was not ignored, both for
CL_UNORM_SHORT_555 and for CL_UNORM_INT_101010.
Fix this by adding a new compare_scanlines() function, which is used for
both of these formats, and does not modify the actual or reference data.
Signed-off-by: Stuart Brady <stuart.brady@arm.com>