add "parallel private" scenario

graph.yml

@@ -8,6 +8,7 @@ tests:
   - shortcut_destination: 20000
   - long_route_destination: 20000
   - parallel_channels_destination: 20000
+  - parallel_private_destination: 20000
 
 # Define a set of policies that are to be used in the channel definitions below.
 policies:
@@ -51,6 +52,9 @@ nodes:
   parallel_channels_destination:
     policy: cheap
 
+  parallel_private_destination:
+    policy: cheap
+
   start:
     policy: normal
     channels:
@@ -93,6 +97,9 @@ nodes:
       # the payment needs to be split into two parts, one for each parallel channel to the destination
       parallel_channels_x:
         - capacity: 1000000
+      # as above, but one private channel needs to be traversed
+      parallel_private_x:
+        - capacity: 1000000
 
   node0_0:
     policy: normal
@@ -412,3 +419,13 @@ nodes:
           remoteBalance: 976000
         - capacity: 1000000
           remoteBalance: 976000
+
+  parallel_private_x:
+    policy: cheap
+    channels:
+      parallel_private_destination:
+        - capacity: 1000000
+          remoteBalance: 976000
+        - capacity: 1000000
+          remoteBalance: 976000
+          private: true