avcodec/golomb: Consume invalid data in get_ur_golomb_jpegls()

Fixes slow loops on fuzzed data
Fixes: 245/fuzz-3-ffmpeg_AUDIO_AV_CODEC_ID_FLAC_fuzzer

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