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

Project: git://git.ghostscript.com/mupdf.git Detailed report: https://oss-fuzz.com/testcase?key=4834102571171840 Project: mupdf Fuzzer: aflmupdfpdffuzzer Fuzz target binary: pdffuzzer Job Type: aflasanmupdf Platform Id: linux Crash Type: Heap-use-after-free READ 4 Crash Address: 0x613000000040...