[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 5b0e827521)

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

Lib/_pyio.py

@@ -407,6 +407,9 @@ class IOBase(metaclass=abc.ABCMeta):
         if closed:
             return
 
+        if dealloc_warn := getattr(self, "_dealloc_warn", None):
+            dealloc_warn(self)
+
         # If close() fails, the caller logs the exception with
         # sys.unraisablehook. close() must be called at the end at __del__().
         self.close()
@@ -853,6 +856,10 @@ class _BufferedIOMixin(BufferedIOBase):
         else:
             return "<{}.{} name={!r}>".format(modname, clsname, name)
 
+    def _dealloc_warn(self, source):
+        if dealloc_warn := getattr(self.raw, "_dealloc_warn", None):
+            dealloc_warn(source)
+
     ### Lower-level APIs ###
 
     def fileno(self):
@@ -1601,12 +1608,11 @@ class FileIO(RawIOBase):
             raise
         self._fd = fd
 
-    def __del__(self):
+    def _dealloc_warn(self, source):
         if self._fd >= 0 and self._closefd and not self.closed:
             import warnings
-            warnings.warn('unclosed file %r' % (self,), ResourceWarning,
+            warnings.warn(f'unclosed file {source!r}', ResourceWarning,
                           stacklevel=2, source=self)
-            self.close()
 
     def __getstate__(self):
         raise TypeError(f"cannot pickle {self.__class__.__name__!r} object")
@@ -1781,7 +1787,7 @@ class FileIO(RawIOBase):
         if not self.closed:
             self._stat_atopen = None
             try:
-                if self._closefd:
+                if self._closefd and self._fd >= 0:
                     os.close(self._fd)
             finally:
                 super().close()
@@ -2690,6 +2696,10 @@ class TextIOWrapper(TextIOBase):
     def newlines(self):
         return self._decoder.newlines if self._decoder else None
 
+    def _dealloc_warn(self, source):
+        if dealloc_warn := getattr(self.buffer, "_dealloc_warn", None):
+            dealloc_warn(source)
+
 
 class StringIO(TextIOWrapper):
     """Text I/O implementation using an in-memory buffer.