WIP: Index global records once

I'm not sure about this fix - but I think the problem is real, and may be part of the issue affecting large migrations. For example, if you migrate an AT or Archon db with 5 repositories and 10000 agents, it looks like you'll post 50000 documents to solr.

*Note: you can run the test against a running backend, but I haven't quite gotten that bug free. Best to run it without ENV['ASPACE_BACKEND_URL']