make F5 and Fortinet tests go through config-pulling (up to the point of tunnel conne...

make F5 and Fortinet tests go through config-pulling (up to the point of tunnel connection), rather than stopping after authentication

The fake servers don't actually implement the tunnel, but they do implement
the pre-tunnel configuration endpoints, and then simulate a "cookie rejected"
response upon tunnel connection.

OpenConnect distinguishes “cookie rejected” errors via an exit status of 2,
whereas any other failure results in an exit status of 1.

Signed-off-by: Daniel Lenski <dlenski@gmail.com>