HTTPS and ICMP latency are fallbacks when STUN doesn't work. The lowest
value wins. When ICMP doesn't work you just get HTTPS. HTTPS latency was
way more variable than it needed to be as we were measuring "server
processing time" (inclusive of TLS, HTTPS) instead of just TCP connect
time.
We don't need to perform an HTTPS request, we really just need a TCP
ping, but aiming for a simpler change to start.
Updates tailscale/corp#22114
Signed-off-by: Jordan Whited <jordan@tailscale.com>
ac0f1cfcf4