Stop using tokio in test which runs all futures sync

[pgerber]

futures::executor::block_on() runs a future to completion in the current thread and there as nothing being spawned to a worker thread (e.g. tokio::spawn()).

Let's make it clear that nothing is running on the tokio runtime by removing it.

I'm not sure this is the right approach. Is there something here you explicitly want to have tested on the tokio runtime or perhaps even a different thread?

[palfrey]

Good catch. I suspect mostly copy/paste from the referenced Stack Overflow answer. The only thing that needed testing was that an async function run entirely within the catch_unwind block still did the correct cleanup in the face of an assertion, and the block_on does that.

Thanks!