Managed zone tests are failing because we're attempting to use the naked
domain as the managed zone, when it's already being managed by GCP. By
making a subdomain the managed zone, we avoid this problem.
This reverts commit 8ab9d96d25 and revives
the original commit that adds t.Parallel to all acceptance tests. It
turns out test failures were unrelated to this change (rather, they were
related to quota issues).
This reverts commit 42de44592f. It appears
there might be thread-safety issues as panics have started occuring when
parallism is ramped up. Reverting for now while investigating.
