Remove integration test setup and teardown

Starting and stopping of the service in setup and teardown is prone
to race conditions and generally brittle. Additionally, eliminating
service life-cycle management from the tests makes them more flexible
by allowing us to run them against arbitrary environments (for example,
in staging as a pre-deployment validation).

Bug: T206016
Change-Id: I13fc23a72ae45874da8a201abe60eeb23b0267d3