Fix flaky router Tests
- Fix flaky router Tests because of uncontrolled timer
The TestRouter_*
tests sporadically failed with an unexpected call to
the mock_reverse_tunnel_tunnel.MockPollingQuerier.PollKasUrlsByAgentId
mock. This was, because there is a timer in the KAS tunnel finder
(see
https://gitlab.com/gitlab-org/cluster-integration/gitlab-agent/-/blob/4855869ee465bd0762e9586d624e1691a945dbcd/cmd/kas/kasapp/router_kas_tunnel_finder.go#L110-110)
that wasn't controlled during the test and this timer triggered after
10ms
the mock. However, we don't really want that, because it's out of
the scope for the affected tests.
Fixes #463 (closed)