Association cache was not reloaded on order_decorator after creating drop ship orders through supplier object in create_drop_ship_orders.
This will be empty in finalize_with_drop_ship! when we try to iterate through drop ship orders to send supplier email.
added flag to force association reload & send email.

Existing Test past because association cache was empty so expectations were never actually set on drop ship orders.  Refactored tests to capture deliver! call count.