Fixes: Timeout (78 sec -> 15 millisec)
Fixes: 13147/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JV_fuzzer-5727107827630080

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>