Remove Regex::PCRE2#finalize redefinition

[HertzDevil]

This redefinition made very simple snippets like below run out of memory eventually:

while true
  Regex.new("")
end

It might be related to #13306 and some other recent memory blow-ups too.

[straight-shoota]

Great find 🚀 🙈
But generating the docs still stalls: https://github.com/crystal-lang/crystal/actions/runs/4683438004/jobs/8298519048?pr=13309
So it doesn't seem to fix that.

[HertzDevil]

d60fe6c: LibPCRE2.code_free can be called freely even in Crystal's interpreter, because it is a regular lib fun, not an extern Proc-typed variable, unlike LibPCRE.free (#12495).

[beta-ziliani]

The interpreter spec failure seems to be unrelated (it's been failing occasionally on the same point)