memory-management

the CONTRIBUTING.md and DEVELOPERS_GUIDE.md need to cross reference.

I was just thinking making sure that it works as a valid execution policy. So simply launch a Thrust algorithm with device data and make sure the result is sound.

I was going to say "just do what we do for our current tests", but apparently that's nothing!

Originally posted by @jrhemstad in rapidsai/rmm#1009 (comment)