spanner: fix tests
spanner: fix tests

- Removed t.Name(), which doesn't work before 1.8

- Removed t.Parallel() from integration tests. They
  can't be run in parallel because they share globals.

Change-Id: Id77219d2d455812ef78ed6a2ad35947d8b50e884
Reviewed-on: https://code-review.googlesource.com/15110
Reviewed-by: Sarah Adams <2b342d1c32491b4e7587e4a0e291a5f0f95d4167@google.com>
Reviewed-by: Di Xiao <ec9213d8904b2f943c1baacd49a0768011ed5ff4@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go