Connecting s_out on a LIF to a_in leads to a deadlock with no warning or error.

[tim-shea]

Describe the bug
If I connect the s_out port of a LIF to its own a_in port, running the model will cause a deadlock, but no error message is generated.

To reproduce current behavior
Create a LIF, connect s_out to a_in, run the LIF.

Expected behavior
An error message should be produced when connect is called if the arguments are not valid.

Environment (please complete the following information):

• Lava version 0.8.0