Handle the case where we recreate an auth context.

Add (opt-in) debugging for refcounts on auth contexts.

This brings the Windows port more in-par with Linux. We're now making sure all of the pollsets are going to return immediately before calling the shutdown callback.

Clean up anything that failed

In the case we're using a threadpool, depending on where the threads are waiting in completion queue's next, they'll get stuck on shutdown because we're only kicking one of them. Instead, let's cascade-kick the pollsets when we shutdown so that we make sure all of them are exitting properly.

Fixes #2190. In grpc_pollset_work we need to pass down which lock to unlock before actually doing something.

Fixes https://github.com/grpc/grpc/issues/2194 .

Part of fixing https://github.com/grpc/grpc/issues/2192

Part of fixing https://github.com/grpc/grpc/issues/2192

Part of fixing https://github.com/grpc/grpc/issues/2192

Part of fixing https://github.com/grpc/grpc/issues/2192

- grpc ruby 0.9.3 should have released from the release branch but was not
- it needs to be re-released from that branch

It shouldn't count towards coverage