Eliminate the need for the Column.zDflt (using Column.pDflt instead) to reduce

the amount of memory needed to hold the schema.

FossilOrigin-Name: d8c94a46dfa94930732c2de2aa79675c5087d36e

src/expr.c

@@ -3070,6 +3070,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       sqlite3ReleaseTempReg(pParse, r4);
       break;
     }
+    case TK_SPAN:
     case TK_COLLATE: 
     case TK_UPLUS: {
       inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);