ec65c53 replaces the usage of `PeerInTest` with `Peer` in
test_lnpeer.py.
PeerInTests sets `Peer.DELAY_INC_MSG_PROCESSING_SLEEP` to 0 so all
incoming messages get processed immediately. Because `Peer` instead of
`TestInPeer` was used the delay caused `test_reestablish_with_old_state`
to fail regularly because bob receives the old channel state and kills
the OldTaskGroup of the unittest with GracefulDisconnect before Alice
processed the answer of Bob and is still in ChannelState.REESTABLISHING.
```
FAILED tests/test_lnpeer.py::TestPeerDirect::test_reestablish_with_old_state - AssertionError: <PeerState.REESTABLISHING: 1> != <PeerState.BAD: 3>
```
dee2371738