utils: Remove obsolete comment
utils: Remove obsolete comment

strings.IndexByte is slower
aperera/mysql,yyljlyy/mysql,sunjian1/mysql,chinanjjohn2012/mysql,cxflag203/mysql,helight/helight_code,siriele/mysql,nanata1115/mysql,yonglehou/mysql,helight/helight_code,netroby/mysql,springning/mysql,methane/mysql,VividCortex/mysql,Vorstack/mysql,segmentio/mysql,segmentio/mysql,LightKool/mysql-go,VividCortex/mysql,helight/helight_code,wfxiang08/mysql,bookerzzz/mysql,methane/mysql,hyperworks/mysql,muthusubbu459/mysql,jockchou/mysql,LightKool/mysql-go,helight/helight_code,zhgo/mysql,rafaeljusto/mysql,Go-SQL-Driver/MySQL,helight/helight_code,go-sql-driver/mysql,helight/helight_code,helight/helight_code,eklitzke/mysql,Freeaqingme/golang-sql-driver-mysql,hebihui/mysql,helight/helight_code,rlowe/mysql,bookerzzz/mysql,Frca/mysql,helight/helight_code,tmulchay/mysql,henrylee2cn/mysql,cw2018/mysql