hcforwarder: Fix integration test false negatives
Randomly we would get a CI fail with TestPin() complaining about getIPIP not capturing anything in 5 seconds.
Internally getIPIP was using a 2 seconds timeout to capture packets, removing this timeout and letting the caller control when the capturing goroutine needs to be stopped seems to fix the false negative
This MR ships commits from !62 (merged) and !63 (merged)