make bench_test.go work again (#5618)
make bench_test.go work again (#5618)


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