Iron golems created by players don't drop their pumpkins when killed

Related to MC-189840. If snow golems are intended to drop their pumpkins, iron golems created by players might be expected to do the same. However, this should only apply to player-created iron golems to prevent iron farms from also producing pumpkins. Whether this is intentional or a feature request is up to Mojang to decide.

Steps to reproduce

1. Build an iron golem
2. Kill the iron golem

Observed result: The pumpkin is not given back.
Expected result: The pumpkin should be dropped so you can retrieve it.

Note: This might be intentional, as iron golems don't drop all the iron they were made from.