[tor-relays] Guard flag flapping

I had already run tests with both speedtest-cli and iperf3. This server consistently achieves 200 to 300 Mb/s in both directions, with both relays still running, and on some runs is hitting over 800 Mb/s.

Final caveats:

If the server is on a shared gigabit link, performance may not improve. The difference between a dedicated gigabit and a shared gigabit is immense. One expects an ISP to load a shared GB links as heavily as possible--I.E. up to the point where customers complain and terminate service. True dedicated gigabit links are expensive.

If it's running in a VPS that's showing a gigabit link speed, the number is fiction.