Investigate novel bigquery system test failures

[dhermes]

1. Job state not DONE

======================================================================
FAIL: test_load_table_from_storage_then_dump_table (bigquery.TestBigQuery)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/build/GoogleCloudPlatform/gcloud-python/system_tests/bigquery.py", line 304, in test_load_table_from_storage_then_dump_table
    self.assertTrue(job.state in ('DONE', 'done'))
AssertionError: False is not true

From:

1. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/77509799
2. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/78073572
3. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/95718525
4. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/95827336
5. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/97283623
6. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/98448630
7. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/100920167
8. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/100929401
9. Dataset not cleaned up from previous failed run (or concurrent run)

From:

1. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/77772358
2. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/78113108
3. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/79729612
4. https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/97489872
5. Eventual consistency

======================================================================
FAIL: test_load_table_then_dump_table (bigquery.TestBigQuery)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/build/GoogleCloudPlatform/gcloud-python/system_tests/bigquery.py", line 239, in test_load_table_then_dump_table
    sorted(ROWS, key=by_age))
AssertionError: Lists differ: [] != [('Bhettye Rhubble', 27), ('Wylma Phlyntst[57 chars] 33)]
Second list contains 4 additional elements.
First extra element 0:
('Bhettye Rhubble', 27)
- []
+ [('Bhettye Rhubble', 27),
+  ('Wylma Phlyntstone', 29),
+  ('Phred Phlyntstone', 32),
+  ('Bharney Rhubble', 33)]

From https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/78498010

[dhermes]

@tseaver Concurrent runs make BQ tests fail hard since they can't re-create the dataset. Can we make the dataset name scoped to the millisecond (or microsecond) so there won't be name collisions?

[dhermes]

@tseaver https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/79729612 (the most recent merge) had an issue with the fixed name of the dataset used. I just deleted it by hand from the Cloud Console.

[tseaver]

@dhermes #1131 should address the name-clash on dataset IDs.

[tseaver]

I'm going to call this one done: #1131 handled the dataset ID uniqueness issue, and the remaining timeout / backoff issues are tracked in #1391 / #1619.

[tseaver]

#2050 tidies up the ad-hockery added earlier for these cases.