Shipwrecks generate improperly at converted world borders

Description

Shipwreck tried to generate as two different wood types, at different heights, when on the border of a 1.17.1 and 1.18 pre-release 1 world.

To reproduce:

• Load seed -2340776169731382640 in 1.17.1
• Fly towards 210X/520Z without loading that chunk itself
• Exit game
• Open 1.18 Pre-Release 1 and load the world