Race condition preventing successful integration tests

There are many `tests/` but one of the first ones (`hooks-prepostcreate-inline`) sees envvars being updated for the service.

The problem is that it appears there can be a time when the old revision is accepting requests, when the new revision should be.

In this example, there is a revision that should return "A" and a revision that should return "AB" (through inline pre- and post-create commands) We should only be testing the service after the deployment is complete, so we should be only ever returning the latest revision ("AB").

But polling the service once a second as it deploys shows there's times when "A" returns to the mix:

```
Mon Dec 5 04:29:51 UTC 2022
A
Mon Dec 5 04:29:54 UTC 2022
A
Mon Dec 5 04:29:56 UTC 2022
A
Mon Dec 5 04:29:57 UTC 2022
AB
Mon Dec 5 04:29:59 UTC 2022
AB
Mon Dec 5 04:30:00 UTC 2022
A
Mon Dec 5 04:30:01 UTC 2022
AB
Mon Dec 5 04:30:02 UTC 2022
AB
```

Pending matching against the service logs to establish it was an older revision receiving the request, etc.