Parity:Zombies can gain nautilus shell or fishing rods when they drown

This is a parity issue.

In Java Edition, zombies converted to drowned are never equipped with new items. 

MC-127295

MC-130237
In Bedrock Edition, Zombies converted to drowned are
1% equipped with a fishing rod in the main hand.
8% equipped with a nautilus shell in the offhand
Any equipment the zombie had before conversion is dropped.