[3.14] gh-133982: Run unclosed file test on all io implementations (gh-134165) (gh...

[3.14] gh-133982: Run unclosed file test on all io implementations (gh-134165) (gh-134433)

Update `test_io` `_check_warn_on_dealloc` to use `self.` to dispatch to
different I/O implementations.

Update the `_pyio` implementation to match expected behavior, using the
same `_dealloc_warn` design as the C implementation uses to report the
topmost `__del__` object.

The FileIO one now matches all the others, so can use IOBase. There was
a missing check on closing (self._fd must be valid), add that check
(cherry picked from commit 5b0e82752120a5dc66ce6ee778751d71ba2c33b2)

Co-authored-by: Cody Maloney <cmaloney@users.noreply.github.com>