OSV-2020-124 Dynamic-stack-buffer-overflow in RetrieveFPForSig

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=21758 Crash type: Dynamic-stack-buffer-overflow WRITE 4 Crash state: RetrieveFPForSig DetectSetFastPatternAndItsId SigGroupBuild...