The go-httpstat package has a data race when used with connections that
are performing happy-eyeballs connection setups as we are in the DERP
client. There is a long-stale PR upstream to address this, however
revisiting the purpose of this code suggests we don't really need
httpstat here.
The code populates a latency table that may be used to compare to STUN
latency, which is a lightweight RTT check. Switching out the reported
timing here to simply the request HTTP request RTT avoids the
problematic package.
Fixestailscale/corp#25095
Signed-off-by: James Tucker <james@tailscale.com>