reget buffer can be time consuming, theres no need to do it if failures
occur

Testcase: 9010/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TSCC_fuzzer-6042614817095680

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