Re-activate partner tests

[runspired]

Potential new external partners

• https://github.com/hashicorp/vault
• https://github.com/Esri/hub.js
• https://github.com/discourse/docker_manager
• active-model-adapter

[runspired]

It's unlikely we'll gather much value for a long time from these given the long-tail of upgrades most of them have failed to keep up with, and considering many of them are concepts that will be baked into EmberData during the 5.x series we're unlikely to gain anything by catching them up.