proj4/standard_fuzzer: Crash in pj_read_vgrid_value

Detailed report: https://oss-fuzz.com/testcase?key=5571475164626944 Project: proj4 Fuzzer: libFuzzerproj4standardfuzzer Fuzz target binary: standardfuzzer Job Type: libfuzzerasanproj4 Platform Id: linux Crash Type: UNKNOWN READ Crash Address: 0x0000bfff0530 Crash State: pjreadvgridvalue...