Clean up expectation ordering.

- It was duplicated in Proxy.
- Makes more sense to initialize it in Space init.
Simplify spec.

rspec-mocks lacks the necessary sandboxing to safely
define and run examples from within examples.
rspec-core has and uses this but it's not exposed
for use here.

Instead, we can just trigger the teardown/setup
that happens between examples.

This fixes some rspec-mocks space leakage
that was happening.