util/types: tiny clean up (#2204)
util/types: tiny clean up (#2204)


JinheLin/tidb,simon-xia/tidb,ngaut/tidb,ming-relax/tidb,astaxie/tidb,silenceper/tidb,silentred/tidb,mccxj/tidb,c4pt0r/tidb,zimulala/tidb,tiancaiamao/tidb,pingcap/tidb,gaocegege/tidb,ueizhou/tidb,Nify/tidb,andelf/tidb,c4pt0r/tidb,c4pt0r/tidb,simon-xia/tidb,EvilMcJerkface/tidb,myrice/tidb,ueizhou/tidb,tiancaiamao/tidb,XuHuaiyu/tidb,spongedu/tidb,ngaut/tidb,JinheLin/tidb,coocood/tidb,XuHuaiyu/tidb,zimulala/tidb,pingcap/tidb,c4pt0r/tidb,cosmtrek/tidb,gaocegege/tidb,yuanwhy/tidb,kyle-wang/tidb,liyu4/tidb,zs634134578/tidb,louishust/tidb,yangwenmai/tidb,mccxj/tidb,yuanwhy/tidb,andelf/tidb,anywhy/tidb,ngaut/tidb,8cbx/tidb,pingcap/tidb,EvilMcJerkface/tidb,cosmtrek/tidb,myrice/tidb,pingcap/tidb,liyu4/tidb,qhsong/tidb,astaxie/tidb,kyle-wang/tidb,CodeRushing/tidb,kyle-wang/tidb,spongedu/tidb,ming-relax/tidb,zs634134578/tidb,silenceper/tidb,CodeRushing/tidb,Nify/tidb,yangwenmai/tidb,ngaut/tidb,qiuyesuifeng/tidb,louishust/tidb,c4pt0r/tidb,qiuyesuifeng/tidb,pingcap/tidb,wusphinx/tidb,silentred/tidb,pingcap/tidb,Cofyc/tidb,coocood/tidb,c4pt0r/tidb,8cbx/tidb,qhsong/tidb,kyle-wang/tidb,anywhy/tidb,ngaut/tidb,kyle-wang/tidb,wusphinx/tidb,Cofyc/tidb,ngaut/tidb,kyle-wang/tidb