libchewing: Heap-buffer-overflow in ChoiceTheSame

Detailed report: https://clusterfuzz-external.appspot.com/testcase?key=4536466013159424 Fuzzer: libFuzzerchewingdefaultfuzzer Job Type: libfuzzerasanlibchewing Platform Id: linux Crash Type: Heap-buffer-overflow READ Crash Address: 0x603000050241 Crash State: ChoiceTheSame SetChoiceInfo...