Rename typing._collect_parameters (#118900)

Unfortunately, released versions of typing_extensions
monkeypatch this function without the extra parameter, which makes
it so things break badly if current main is used with typing_extensions.

Fortunately, the monkeypatching is not needed on Python 3.13, because CPython
now implements PEP 696. By renaming the function, we prevent the monkeypatch
from breaking typing.py internals.

We keep the old name (raising a DeprecationWarning) to help other external users who call it.