Cubic performs better than Reno in higher BDP scenarios, and enables the
use of the hystart++ implementation contributed by Coder. This improves
throughput on higher BDP links with a much faster ramp.
gVisor is bumped as well for some fixes related to send queue processing
and RTT tracking.
Updates #9707
Updates #10408
Updates #12393
Updates tailscale/corp#24483
Updates tailscale/corp#25169
Signed-off-by: James Tucker <james@tailscale.com>