store/copr: removes the unused fields in batchCopIterator (#24446)
store/copr: removes the unused fields in batchCopIterator (#24446)

 
c4pt0r/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,pingcap/tidb,ngaut/tidb,kyle-wang/tidb,pingcap/tidb,coocood/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,pingcap/tidb,coocood/tidb,ngaut/tidb,kyle-wang/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb