*: fix resource leak in select for update when 'tidb_low_resolution_t…

…so' is set (#57012) (#57367)

close #55468

pkg/executor/adapter.go

@@ -598,6 +598,7 @@ func (a *ExecStmt) Exec(ctx context.Context) (_ sqlexec.RecordSet, err error) {
 
 	if a.isSelectForUpdate {
 		if sctx.GetSessionVars().UseLowResolutionTSO() {
+			terror.Log(exec.Close(e))
 			return nil, errors.New("can not execute select for update statement when 'tidb_low_resolution_tso' is set")
 		}
 		// Special handle for "select for update statement" in pessimistic transaction.
@@ -614,6 +615,7 @@ func (a *ExecStmt) Exec(ctx context.Context) (_ sqlexec.RecordSet, err error) {
 	var txnStartTS uint64
 	txn, err := sctx.Txn(false)
 	if err != nil {
+		terror.Log(exec.Close(e))
 		return nil, err
 	}
 	if txn.Valid() {