libchewing: Heap-buffer-overflow in SetChoiceInfo

Detailed report: https://clusterfuzz-external.appspot.com/testcase?key=4890595495510016 Target: libchewing Fuzzer: libFuzzerlibchewingchewingdynamicconfigfuzzer Fuzzer binary: chewingdynamicconfigfuzzer Job Type: libfuzzerasanlibchewing Platform Id: linux Crash Type: Heap-buffer-overflow READ 4...