This change reduces the CPU consumption of --help by ~50%.
Also, this change removes ANSI escape codes from our golden files. I
don't think those were worth the inability to parallelize golden file tests and
global state fragility.
- Remove mostly redundant "Transferred" column
- Rename "Bandwidth" to "Throughput"
- Replace "--reverse" (which has an ambiguous starting state) with "--direction=(up|down)"
- Tolerate AgentStartErrors which may be caused by failing startup
script