cache/last: use rowTs instead of lastRowTs

source/dnode/vnode/src/tsdb/tsdbCache.c

@@ -2304,13 +2304,13 @@ static int32_t mergeLastCid(tb_uid_t uid, STsdb *pTsdb, SArray **ppLastArray, SC
         if (slotIds[iCol] == 0) {
           STColumn *pTColumn = &pTSchema->columns[0];
 
-          *pColVal = COL_VAL_VALUE(pTColumn->colId, pTColumn->type, (SValue){.val = lastRowTs});
-          taosArraySet(pColArray, 0, &(SLastCol){.ts = lastRowTs, .colVal = *pColVal});
+          *pColVal = COL_VAL_VALUE(pTColumn->colId, pTColumn->type, (SValue){.val = rowTs});
+          taosArraySet(pColArray, 0, &(SLastCol){.ts = rowTs, .colVal = *pColVal});
           continue;
         }
         tsdbRowGetColVal(pRow, pTSchema, slotIds[iCol], pColVal);
 
-        *pCol = (SLastCol){.ts = lastRowTs, .colVal = *pColVal};
+        *pCol = (SLastCol){.ts = rowTs, .colVal = *pColVal};
         if (IS_VAR_DATA_TYPE(pColVal->type) && pColVal->value.nData > 0) {
           pCol->colVal.value.pData = taosMemoryMalloc(pCol->colVal.value.nData);
           if (pCol->colVal.value.pData == NULL) {