test/decode/tinyjpeg: make sure the pointer is valid before dereferencing it
test/decode/tinyjpeg: make sure the pointer is valid before dereferencing it

Signed-off-by: Xiang, Haihao <8d677183e5993577d4fa73a419b76987913292d6@intel.com>
Reviewed-by: Sean V Kelley <2e220d3765e3e059981b3c8d241463f952b3ee5f@posteo.de>
(cherry picked from commit 8455834161bab3374fe9756fd4a28d919027daf7)

01org/libva-cros,chenxianqin/vaapi-libva,01org/libva-cros,01org/libva-cros,01org/iotg-lin-gfx-libva,chenxianqin/vaapi-libva,chenxianqin/vaapi-libva,01org/iotg-lin-gfx-libva,01org/iotg-lin-gfx-libva