fix goroutine leak in chunk size control test (#9718)
fix goroutine leak in chunk size control test (#9718)


qiuyesuifeng/tidb,XuHuaiyu/tidb,ming-relax/tidb,kyle-wang/tidb,pingcap/tidb,pingcap/tidb,c4pt0r/tidb,c4pt0r/tidb,ngaut/tidb,cosmtrek/tidb,kyle-wang/tidb,EvilMcJerkface/tidb,pingcap/tidb,c4pt0r/tidb,cosmtrek/tidb,kyle-wang/tidb,ngaut/tidb,Cofyc/tidb,pingcap/tidb,Cofyc/tidb,pingcap/tidb,kyle-wang/tidb,ngaut/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,c4pt0r/tidb,kyle-wang/tidb,EvilMcJerkface/tidb,ngaut/tidb,kyle-wang/tidb,coocood/tidb,ming-relax/tidb,XuHuaiyu/tidb,qiuyesuifeng/tidb,ngaut/tidb,coocood/tidb,c4pt0r/tidb