bpo-43970: Optimize Path.cwd() in pathlib by not instantiating a class unnecessarily (GH-25699)

diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index 073fce8..cf40370 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -978,7 +978,7 @@ def cwd(cls):
         """Return a new path pointing to the current working directory
         (as returned by os.getcwd()).
         """
-        return cls(cls()._accessor.getcwd())
+        return cls(cls._accessor.getcwd())
 
     @classmethod
     def home(cls):