libchewing: Heap-buffer-overflow in ueStrNBytes

Detailed report: https://clusterfuzz-external.appspot.com/testcase?key=6274152528871424 Target: libchewing Fuzzer: libFuzzerlibchewingchewingrandominitfuzzer Fuzzer binary: chewingrandominitfuzzer Job Type: libfuzzerasanlibchewing Platform Id: linux Crash Type: Heap-buffer-overflow READ 1 Crash...