OSV-2020-578 Heap-use-after-free in WelsDec::ResetRefPicReferences

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13450 Crash type: Heap-use-after-free READ 8 Crash state: WelsDec::ResetRefPicReferences WelsDec::DecreasePicBuff WelsRequestMem...