Fix potential tax calculation issues with charging of unreturned expedited exchanges

* Test that taxes are included
* Make sure to hit all state machine transition events

Conflicts:
	core/lib/tasks/exchanges.rake
sorry didnt meant to leave that, it's tested here https://github.com/spree/spree/pull/5237/files#diff-022419e1e17ca9e7dccebd6bb8d6f685R83. i'll remove that one