[MC-129105] Shipwrecks can generate inside iceberg

I noticed a shipwreck on the surface in an iceberg. Normally shipwrecks generate underwater. Accessing it is almost impossible.

Seed : -3327957343374216397

/tp @s 725.55 76.00 -1104.62 -2201.40 89.70

/tp @s 725.55 76.00 -1104.62 -2201.40 89.70

Linked issues

Shipwrecks can also generate inside the ocean floor, and into the sides of underwater hills

Shipwreck no longer generate inside iceberg in 1.13-pre6. It is fixed ~~but now generate below the iceberg~~