The ICMP Tor enforcement test is fragile

This is about the scenario ‘The Tor enforcement is effective at blocking untorified ICMP connection’. The ‘the untorified connection is logged as dropped by the firewall’ step sometimes fails with No ICMP packet to 1.2.3.4 was dropped by the firewall.

One idea is that the lines haven’t been logged by the kernel yet, or that kernel message throttling has kicked in.

Feature Branch: https://salsa.debian.org/tails-team/tails/merge_requests/33

Parent Task: #10288

Original created by @anonym on 10499 (Redmine)