graph/db+sqldb: impl PutClosedScid and IsClosedScid

graph/db/graph_test.go

@@ -4325,7 +4325,7 @@ func TestGraphLoading(t *testing.T) {
 func TestClosedScid(t *testing.T) {
 	t.Parallel()
 
-	graph := MakeTestGraph(t)
+	graph := MakeTestGraphNew(t)
 
 	scid := lnwire.ShortChannelID{}