Duke3D: Clipping issue in Caribbean Secret Level (VACASL.map)

Found by Ninety-Six on duke4.

The following table holds a secret and the player should be able to crouch under it: https://i.imgur.com/yyb94bh.png

However, as of the time of writing this is no longer possible, and the player cannot pass under the table at all.

Originally broken with d060ca95, fixed by 54e67e4b , and then broken again by d2a530cd.

Map file to reproduce: vaca_clipping03.map