OSV-2020-2024 Heap-buffer-overflow in pixFindHorizontalRuns

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26268 Crash type: Heap-buffer-overflow WRITE 4 Crash state: pixFindHorizontalRuns pixFillPolygon graphicsfuzzer.cc...