gh-101196: Make isdir/isfile/exists faster on Windows (GH-101324)

Co-authored-by: Eryk Sun <eryksun@gmail.com>

Lib/ntpath.py

@@ -276,19 +276,6 @@ def dirname(p):
     """Returns the directory component of a pathname"""
     return split(p)[0]
 
-# Is a path a symbolic link?
-# This will always return false on systems where os.lstat doesn't exist.
-
-def islink(path):
-    """Test whether a path is a symbolic link.
-    This will always return false for Windows prior to 6.0.
-    """
-    try:
-        st = os.lstat(path)
-    except (OSError, ValueError, AttributeError):
-        return False
-    return stat.S_ISLNK(st.st_mode)
-
 
 # Is a path a junction?
 
@@ -870,11 +857,13 @@ def commonpath(paths):
 
 
 try:
-    # The genericpath.isdir implementation uses os.stat and checks the mode
-    # attribute to tell whether or not the path is a directory.
-    # This is overkill on Windows - just pass the path to GetFileAttributes
-    # and check the attribute from there.
-    from nt import _isdir as isdir
+    # The isdir(), isfile(), islink() and exists() implementations in
+    # genericpath use os.stat(). This is overkill on Windows. Use simpler
+    # builtin functions if they are available.
+    from nt import _path_isdir as isdir
+    from nt import _path_isfile as isfile
+    from nt import _path_islink as islink
+    from nt import _path_exists as exists
 except ImportError:
-    # Use genericpath.isdir as imported above.
+    # Use genericpath.* as imported above
     pass