Drop test case that's problematic in 3.11

This is already covered in test_ntpath.py.

Author: barneygale

Lib/test/test_pathlib/test_join_windows.py

@@ -40,8 +40,6 @@ def test_join(self):
         pp = p.joinpath('E:d:s')
         self.assertEqual(pp, P('E:d:s'))
         # Joining onto a UNC path with no root
-        pp = P('//').joinpath('server')
-        self.assertEqual(pp, P('//server'))
         pp = P('//server').joinpath('share')
         self.assertEqual(pp, P(r'//server\share'))
         pp = P('//./BootPartition').joinpath('Windows')