Experimental code that tries to put the computation of subqueries inside a

subroutine, and reuse that subroutine if the same subquery is evaluated more
than once.  Current code does not work for CHECK constraints.

FossilOrigin-Name: 6c44838adbe5dc482bc010e91a6dd7a0f777c989f443dd600740d2c783208e0d

src/where.c

@@ -854,6 +854,7 @@ static void constructAutomaticIndex(
     translateColumnToCopy(pParse, addrTop, pLevel->iTabCur,
                           pTabItem->regResult, 1);
     sqlite3VdbeGoto(v, addrTop);
+    pTabItem->fg.viaCoroutine = 0;
   }else{
     sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v);
   }