Work toward improving the NGQP's ability to optimize out ORDER BY clauses.

FossilOrigin-Name: 67367f1e1f0c3eb6be65eea9873910aa62b49884
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 3ba0a35..176413c 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1919,8 +1919,8 @@
 ** contains more than 63 columns and the 64-th or later column is used.
 */
 struct SrcList {
-  i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
-  i16 nAlloc;      /* Number of entries allocated in a[] below */
+  u8 nSrc;        /* Number of tables or subqueries in the FROM clause */
+  u8 nAlloc;      /* Number of entries allocated in a[] below */
   struct SrcList_item {
     Schema *pSchema;  /* Schema to which this item is fixed */
     char *zDatabase;  /* Name of database holding this table */