perf change (#8796) (#8797)

Co-authored-by: Alessio Treglia <alessio@tendermint.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
(cherry picked from commit e17953a)

Co-authored-by: Marko <marbar3778@yahoo.com>

store/cachekv/memiterator.go

@@ -19,7 +19,7 @@ type memIterator struct {
 }
 
 func newMemIterator(start, end []byte, items *list.List, ascending bool) *memIterator {
-	itemsInDomain := make([]*kv.Pair, 0)
+	itemsInDomain := make([]*kv.Pair, 0, items.Len())
 
 	var entered bool