fix infinite loop in yaramods tokenizer

[mikicaivosevic]

printf '/*\xff' > poc.yar - parsing poc.yar never returns. 100% CPU, flat memory (~9.5 MB constant), no exception, no allocation growth. Only SIGKILL ends it.

$ pip install yaramod # 4.8.1
$ cat poc.py

import yaramod
open('poc.yar', 'wb').write(b'/*\xff')
yaramod.Yaramod().parse_file('poc.yar')   <-- never returns

$ python poc.py
hangs indefinitely; 100% of one core;