OSV-2020-1671 Heap-buffer-overflow in Dasher::Dasher

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25243 Crash type: Heap-buffer-overflow READ 4 Crash state: Dasher::Dasher bool drawLineAA& QCosmeticStroker::drawPath...