[netemul] Relax setup timeouts

BUG: FLK-89 #comment

- Relax global setup timeouts and helper_netstack_cfg timeout.
- Logs in reported flake suggest that the timeout is too strict.
- Adds more verbosity to helper_netstack_cfg so it's easier to diagnose
where it got stuck.

Change-Id: I9975440fe3c9fb0d30492f5671785a76f367f37f