OSV-2021-1070 Heap-buffer-overflow in ZSTD_decompressBlock_internal

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=36623 Crash type: Heap-buffer-overflow READ 4 Crash state: ZSTDdecompressBlockinternal ZSTDdecompressMultiFrame ZSTDdecompressDCtx...