Adapt tests to use batch suspendable request core

[gavin-norman-sociomantic]

Adapting the swarm neo test to work with two nodes, as part of #192, the suspend GetAll test hangs.

This appears to be due to a bug in SuspendableRequestCore. As debugging such code is pretty laborious, and it's essentially deprecated, I won't dig into it. Instead, we should adapt the tests to use the newer batch suspendable core.

[gavin-norman-sociomantic]

As #209 touches this code as well, it's probably worth delaying this issue until after #209 is merged (to avoid conflicts).

[gavin-norman-sociomantic]

This is non-essential. I'd prefer to release v4.5.0 and address this in the next milestone.

[gavin-norman-sociomantic]

I've got half way through converting the test GetAll request to use the current batch request core. It's not easy, though, and I get the feeling it'll take quite some time to get it working properly. I'd suggest that we instead move this issue to v4.7.0, and do it based on the new framework in #243.