This exercises the branch path of ```deactivate_osrandom_engine()``` where you call deactivate but the current default_RAND is not osrandom. In this case deactivate should be a noop since we only want to deactivate the engine if it's osrandom, not if someone has changed the engine.

This is a pretty big edge case, so one way we could avoid this is by changing it to something like ```activate_builtin_random()```. With a method call like that we could just deactivate **any** default engine and not worry about which one is actually default.