[3.14] gh-133485: Use interpreters.Interpreter in InterpreterPoolExecutor (gh-135695)

Most importantly, this resolves the issues with functions and types defined in __main__.
It also expands the number of supported objects and simplifies the implementation.

(cherry picked from commit 725da50520, AKA gh-133957)

Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>