GH-113528: Deoptimise pathlib._abc.PurePathBase.name (#113531)

Replace usage of `_from_parsed_parts()` with `with_segments()` in
`with_name()`, and take a similar approach in `name` for consistency's
sake.

Lib/pathlib/__init__.py

@@ -166,6 +166,25 @@ class PurePath(_abc.PurePathBase):
             return NotImplemented
         return self._parts_normcase >= other._parts_normcase
 
+    @property
+    def name(self):
+        """The final path component, if any."""
+        tail = self._tail
+        if not tail:
+            return ''
+        return tail[-1]
+
+    def with_name(self, name):
+        """Return a new path with the file name changed."""
+        m = self.pathmod
+        if not name or m.sep in name or (m.altsep and m.altsep in name) or name == '.':
+            raise ValueError(f"Invalid name {name!r}")
+        tail = self._tail.copy()
+        if not tail:
+            raise ValueError(f"{self!r} has an empty name")
+        tail[-1] = name
+        return self._from_parsed_parts(self.drive, self.root, tail)
+
     def relative_to(self, other, /, *_deprecated, walk_up=False):
         """Return the relative path to another path identified by the passed
         arguments.  If the operation is not possible (because this is not