In commit 7710efc5f9 we corrected the handling of large chests as the
destination for hoppers moving items but did not apply the same fix for
large chests being the source or for droppers. This commit updates these
to have the same fix.
Large chests work in a different fashion as they are a combination of
two other inventories. This causes their getOwner method to always return
null as their is no correct return. To compensate for this for the hopper
events we special case them to use their CraftBukkit counterpart that has
the information we need for the event.
