selftests: fib_rule_tests: Add port range match tests

Currently, only matching on specific ports is tested. Add port range
testing to make sure this use case does not regress.

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250217134109.311176-8-idosch@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>