Simplify the accumulator reset for aggregate query processing so that it
uses a single multi-register OP_Null rather than a separate OP_Null for each
register.

FossilOrigin-Name: 2c7fd9b043f5f3d9d8e22dbefa84a9770ca951d0
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index af018ed..a33ff4d 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1688,6 +1688,7 @@
   int sortingIdx;         /* Cursor number of the sorting index */
   int sortingIdxPTab;     /* Cursor number of pseudo-table */
   int nSortingColumn;     /* Number of columns in the sorting index */
+  int mnReg, mxReg;       /* Range of registers allocated for aCol and aFunc */
   ExprList *pGroupBy;     /* The group by clause */
   struct AggInfo_col {    /* For each column used in source tables */
     Table *pTab;             /* Source table */