Some natc instances have been observed with excessive memory growth,
dominant in gvisor buffers. It is likely that the connection buffers are
sticking around for too long due to the default long segment time, and
uptuned buffer size applied by default in wgengine/netstack. Apply
configurations in natc specifically which are a better match for the
natc use case, most notably a 5s maximum segment lifetime.
Updates tailscale/corp#25169
Signed-off-by: James Tucker <james@tailscale.com>
ca39c4e150