CI: Multi-monitor test is resilient to  misalignments
CI: Multi-monitor test is resilient to  misalignments

We previously randomly sampled lines from the first monitor's output
and compared them to the others. Due to scheduling differences for each
invocation of monitor, we also skipped some lines to account for one
instance seeing traffic earlier than another. This was susceptible to
instances where 5 skipped lines was not enough.
This change switches the code to look for the presence of the shortest
monitor output in all the others, without ordering differences or
additions/removals.

Signed-off-by: Ray Bejjani <7f525154e857f3d57a641a83dddc584f42addc6a@covalent.io>

tgraf/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium-team/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,cilium-team/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium