expression: remove useless code (#13439)
expression: remove useless code (#13439)


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