mupdf/pdf_fuzzer: Heap-use-after-free in fz_drop_imp

Project: git://git.ghostscript.com/mupdf.git Detailed report: https://oss-fuzz.com/testcase?key=5782684270854144 Project: mupdf Fuzzer: aflmupdfpdffuzzer Fuzz target binary: pdffuzzer Job Type: aflasanmupdf Platform Id: linux Crash Type: Heap-use-after-free READ 4 Crash Address: 0x6080000005a0...