Fix the toxins test site

[iyaerP]

I just logged back in today for the first time in a couple months and heard that the bomb code had changed, so I wanted to do some testing. Well, turns out I could only perform a single test because at some point the adminwall at the bomb test site, used for making sure that bombs don't fly into space after the first test, got removed at some point, so now it is impossible to perform more than a single test without having to rebuild the bomb site. When I tried to do so, I got eaten by a pack of space carp. This is retardedly bad design, and should get reverted immediately.

[Jeb]

Fairly certain there was a PR that was supposed to fix it, think it was caused by unsimulated turfs not being a thing anymore or something like that.

[iyaerP]

Okay.