optimizer: clean up again.
optimizer: clean up again.

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