libchewing: Heap-buffer-overflow in ChewingIsChiAt

Detailed report: https://clusterfuzz-external.appspot.com/testcase?key=5628163484811264 Fuzzer: libFuzzerchewingdynamicconfigfuzzer Job Type: libfuzzerasanlibchewing Platform Id: linux Crash Type: Heap-buffer-overflow READ 4 Crash Address: 0x7fa078bd0fb0 Crash State: ChewingIsChiAt CallPhrasing...