connection-manager: fix test

When running connection manager with two outbound connection, the second
overlapping with the first one we now do (in the specified order):

* `unregisterInboundConncection`: `TimeoutExpired` transition
* `unregisterOutboundConnection`: `DemotedToCold^{Duplex}_{Local}
                                    : OutboundState df
                                    → PreTerminatingState df`
   which terminates the connection after reset delay (5s)

Rather than the other way around, which would do:

* `unregisterOutboundConnection`: `DemotedToCold^{Duplex}_{Local}
                                    : OutboundState df
                                    → InboundIdleState df`
* `unregisterInboundConnection`: `DemotedToCold^{Duplex}_{Remote}
                                    : InboundIdleState df
                                    → TerminatingState`
   which terminates the connection without a delay

This change is needed because in the second case the connection is
closed and the test environment is expected to return an fd, but
since the schedule for the second connection has set 'siExists' to
'True' an fd is not present, which results in test environment failure.

Another reason to switch the order is that the second case is already
tested when there's an inbound connection.

ouroboros-network-framework/test/Test/Ouroboros/Network/ConnectionManager.hs

@@ -1995,16 +1995,19 @@ prop_connectionManagerSimulation (SkewedBool bindToLocalAddress) scheduleMap =
                               case seActiveDelay conn of
                                 Left  _ -> killThread (hThreadId handle)
                                 Right _ -> do
-                                  (res, _) <-
-                                    unregisterOutboundConnection
-                                      connectionManager addr
-                                    `concurrently`
-                                      (when ( not (siReused (seExtra conn))
-                                              && seDataFlow conn == Duplex ) $
-                                         void $
-                                           unregisterInboundConnection
-                                             connectionManager addr
-                                      )
+                                  when ( not (siReused (seExtra conn))
+                                         && seDataFlow conn == Duplex ) $
+                                    -- we need to perform the @TimeoutExpired@
+                                    -- transition, in order for
+                                    -- 'unregisterOutboundConnection' to be
+                                    -- successful.
+                                    void $
+                                      unregisterInboundConnection
+                                        connectionManager addr
+
+                                  res <-
+                                      unregisterOutboundConnection
+                                        connectionManager addr
                                   case res of
                                     UnsupportedState st ->
                                       throwIO (UnsupportedStateError
@@ -2105,8 +2108,10 @@ prop_connectionManagerSimulation (SkewedBool bindToLocalAddress) scheduleMap =
         -- will fail.
         Just (SomeConnectionManagerError e@ImpossibleConnection {}) -> throwIO e
         Just (SomeConnectionManagerError e@ImpossibleState {})      -> throwIO e
+        -- the test environment can requests outbound connection when there is
+        -- one in 'PreTerminatingState'
         Just (SomeConnectionManagerError  (ForbiddenOperation _
-                                            (OutboundIdleSt Unidirectional) _))
+                                            (OutboundIdleSt _) _))
                                          -> pure ()
         Just (SomeConnectionManagerError e@ForbiddenOperation {})   -> throwIO e
         Just (SomeConnectionManagerError e@UnknownPeer {})          -> throwIO e