redirecttraffic: fix a flaky test
https://app.circleci.com/pipelines/github/hashicorp/consul-enterprise/6408/workflows/e90b1140-daa2-458f-8197-d1821e3693e3/jobs/94694/tests#failed-test-0
The ExcludeInboundPorts can be in a different order sometimes, although I'm not sure how.
Also removes t.Parallel. We should only need to use t.Parallel in large packages with many slow tests.
In this case there is only a single slow test so we don't get any benefit.
Also add struct field names to the testcases list, so that it is easier to see what
each value is doing, and to make it easier to add new fields in the future.
f079cef352