gdal/gtiff_mmap: Crash in DumpModeDecode

Project: https://github.com/OSGeo/gdal.git Detailed report: https://oss-fuzz.com/testcase?key=5743325837000704 Project: gdal Fuzzer: libFuzzergdalgtiffmmap Fuzz target binary: gtiffmmap Job Type: libfuzzerubsangdal Platform Id: linux Crash Type: UNKNOWN READ Crash Address: 0x00000a30fc38 Crash...