B 33971/global setup teardown

We have a body of integration test suites currently running sequentially.  We need these to run in parallel.  However, each setUp procedure attempts to establish some global resource; e.g., a Cassandra schema.  A batch of five schema restores running all at once leaves all five tests in a failure state, since Cassandra insists that the versions are all out of date.

This PR adds a feature to Whiskey which allows us to pull that common initialization code out into a single globalSetUp that is run for the _entire_ batch of test suites.  This way, the Cassandra code executes exactly once., regardless of parallelism used.