Optimization to the ExprList object to make it slightly smaller and faster.

FossilOrigin-Name: 4da49a95c0f07ed7790169e8833c3e2dacda504a3d997f567572020148abe30b

src/sqliteInt.h

@@ -2468,7 +2468,9 @@ struct Expr {
 */
 struct ExprList {
   int nExpr;             /* Number of expressions on the list */
-  int nAlloc;            /* Number of a[] slots allocated */
+#ifdef SQLITE_DEBUG
+  u8 bFixedSize;         /* May not be expanded using sqlite3ExprListAppend() */
+#endif
   struct ExprList_item { /* For each expression in the list */
     Expr *pExpr;            /* The parse tree for this expression */
     char *zName;            /* Token associated with this expression */