Using strncmp() to compare pixel data buffer leads to incorrect tests.
Also, we should clear the pixel data buffer before editing and comparing them.
Signed-off-by: Ziqing Hui <zhui@codeweavers.com>
Signed-off-by: Esme Povirk <esme@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>