multi: use MakeTestGraphNew for all remaining unit tests

And delete the old MakeTestGraph function.

Here we need to update some of our unit tests to ensure that any updates
to existing nodes or channel policies have newer timestamps. This is so
that we don't violate our SQL DB constraints that prevent updates to a
node or channel policy record if the new update is not newer (has a
newer LastUpdate time) than the currently presisted record).

graph/notifications_test.go

@@ -763,7 +763,7 @@ func TestNodeUpdateNotification(t *testing.T) {
 	// then it should trigger a new notification.
 	// TODO(roasbeef): assume monotonic time.
 	nodeUpdateAnn := *node1
-	nodeUpdateAnn.LastUpdate = node1.LastUpdate.Add(300 * time.Millisecond)
+	nodeUpdateAnn.LastUpdate = node1.LastUpdate.Add(time.Second)
 
 	// Add new node topology update to the channel router.
 	if err := ctx.builder.AddNode(ctxb, &nodeUpdateAnn); err != nil {
@@ -1059,7 +1059,7 @@ type testCtx struct {
 func createTestCtxSingleNode(t *testing.T,
 	startingHeight uint32) *testCtx {
 
-	graph := graphdb.MakeTestGraph(t)
+	graph := graphdb.MakeTestGraphNew(t)
 	sourceNode := createTestNode(t)
 
 	require.NoError(t,