In the stay-on-last-page optimization for sqlite3BtreeIndexMoveto()

(check-in [0057bbb508e7662b] about 16 hours ago), be sure
to clear the BTCF_ValidOvfl flag, since the overflow cache is invalidated
by the search on the last page.  OSSFuzz issue 45329.

FossilOrigin-Name: 0021bebc162e001b788786703ce634e7b8fcd3976f7047a5956e82140791e765

src/btree.c

@@ -5837,6 +5837,7 @@ int sqlite3BtreeIndexMoveto(
     if( pCur->iPage>0 
      && (c = indexCellCompare(pCur, 0, pIdxKey, xRecordCompare))<=0
     ){
+      pCur->curFlags &= ~BTCF_ValidOvfl;
       goto bypass_moveto_root;  /* Start search on the current page */
     }
   }