`setup` and `teardown` are each assigning `space` to a new object instance -- so this has the effect of adding two more objects to _every_ example, which can add to the GC time a test suite has.  `ErrorSpace` is stateless so it's fine to re-use the same instance.  `Space` has logic that takes care of clearing things between examples (e.g. `reset_all` clears out its various arrays/hashes), so I think we can re-use the space instance as well (given that was happening before)...

That said, I'm actually leaning towards using a new fresh space for each example, and just removing unneeded logic from `Space#reset_all` (e.g. the `clear` calls), since using a new instance seems like a cleaner way to have clean slate.