Fixes https://github.com/coder/internal/issues/695
PostgreSQL tests are getting run in a non-postgres CI job because the tests don't get skipped if the `DB=` env is unset. This PR adds a skip for them.
They are flaking in the `test-go-race` CI job. They run fine in the `test-go-race-pg` job, which pre-creates the postgres server, so the flakiness is almost certainly related to spinning up the database server.
Spike Curtis
bf0271fd65