[next] "objects" searchBlockmap function in Lua barely functioning

I have yet to find a single Lua script where it's working anymore after !2267 (merged) was merged.

Examples found:

• Silver (telekinesis)
• Bean (bombs)
• Plague Knight (auto-aim, bomb radius damage)
• E-102 Gamma (targeting, blaster radius damage)

There appears to be a tiny random sweet spot where it will detect some objects, but generally it is not working at all.

It also appears to be able to leak memory from a cursory glance at the code, but I haven't tested it. It can return early after P_NewBlockThingsIterator but before P_FreeBlockThingsIterator.