ddl: add column index check test.
ddl: add column index check test.

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