libchewing: Negative-size-param in ChewingKillChar

Project: https://github.com/chewing/libchewing.git Detailed report: https://clusterfuzz-external.appspot.com/testcase?key=6311985729765376 Fuzzer: libFuzzerlibchewingchewingdynamicconfigfuzzer Job Type: libfuzzerasanlibchewing Platform Id: linux Crash Type: Negative-size-param Crash Address: Cras...