[TD-2169]<fix>: fix memory leaks in group by query processing.

src/query/src/qExecutor.c

@@ -1372,8 +1372,12 @@ static int32_t setGroupResultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, char *pDat
   }
 
   if (type == TSDB_DATA_TYPE_BINARY || type == TSDB_DATA_TYPE_NCHAR) {
-    pResultRow->key = malloc(varDataTLen(pData));
-    varDataCopy(pResultRow->key, pData);
+    if (pResultRow->key == NULL) {
+      pResultRow->key = malloc(varDataTLen(pData));
+      varDataCopy(pResultRow->key, pData);
+    } else {
+      assert(memcmp(pResultRow->key, pData, varDataTLen(pData)) == 0);
+    }
   } else {
     pResultRow->win.skey = v;
     pResultRow->win.ekey = v;