ddl: make the test stable (#6223)
ddl: make the test stable (#6223)


kyle-wang/tidb,c4pt0r/tidb,kyle-wang/tidb,tiancaiamao/tidb,EvilMcJerkface/tidb,kyle-wang/tidb,kyle-wang/tidb,ngaut/tidb,tiancaiamao/tidb,ngaut/tidb,cosmtrek/tidb,ngaut/tidb,CodeRushing/tidb,pingcap/tidb,coocood/tidb,c4pt0r/tidb,qiuyesuifeng/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb,cosmtrek/tidb,EvilMcJerkface/tidb,ming-relax/tidb,pingcap/tidb,kyle-wang/tidb,c4pt0r/tidb,wusphinx/tidb,Cofyc/tidb,c4pt0r/tidb,ming-relax/tidb,Nify/tidb,mccxj/tidb,XuHuaiyu/tidb,ngaut/tidb,Cofyc/tidb,CodeRushing/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,wusphinx/tidb,mccxj/tidb,coocood/tidb,c4pt0r/tidb,XuHuaiyu/tidb,pingcap/tidb,Nify/tidb,qiuyesuifeng/tidb