tests/pf/route_to: check_random: rely on test timeout to fail

[siva]

Summary

This test is known to be flaky if 10 attempts happens to be
not enough for the test to pass. Usually, this test passes in ~4-6 attempts.
See https://ci.freebsd.org/job/FreeBSD-main-amd64-test/28664/testReport/junit/sys.netpfil.pf/route_to/random_table/

Rely on the timeout (default 5 mins) to catch a failure here, rather than just 10
attempts. It's very unlikely that 5 mins worth of attempts still isn't enough.

For a history of flakiness, see
https://ci.freebsd.org/job/FreeBSD-main-amd64-test/lastSuccessfulBuild/testReport/junit/sys.netpfil.pf/route_to/random_table/history/

PR: 289477

[ngie]

tests/sys/netpfil/pf/route_to.sh

50–52

Could you please add a comment to note that this infinite loop is intentional? It doesn't have to be overly verbose -- just to ensure that someone doesn't drop the change by accident.
Also, should this have a short sleep to avoid burning a ton of CPU in this loop?

[siva]

Added comment around infinite loop and updated other test related comments.