GH-112906: Fix performance regression in pathlib path initialisation (#112907)

This was caused by 76929fdeeb, specifically its use of `super()` and its
packing/unpacking `*args`.

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Lib/pathlib/__init__.py

@@ -90,7 +90,9 @@ def __init__(self, *args):
                         "object where __fspath__ returns a str, "
                         f"not {type(path).__name__!r}")
                 paths.append(path)
-        super().__init__(*paths)
+        # Avoid calling super().__init__, as an optimisation
+        self._raw_paths = paths
+        self._resolving = False
 
     def __reduce__(self):
         # Using the parts tuple helps share interned path parts