Revert "Fix tests on windows."

This reverts commit 5fe1f6b9f903c95c95ea5bba9f69082b52a7fba1.

dulwich/tests/test_porcelain.py

@@ -1880,13 +1880,11 @@ class StatusTests(PorcelainTestCase):
         )
         self.assertListEqual(results.unstaged, [b"blye"])
         self.assertListEqual(
-            results.untracked, [
-                "untracked_file", os.path.join("untracked_dir", "file")]
+            results.untracked, ["untracked_file", "untracked_dir/file"]
         )
         results_no_walk = porcelain.status(self.repo.path, walk_untracked=False)
         self.assertListEqual(
-            results_no_walk.untracked,
-            ["untracked_file", "untracked_dir" + os.path.sep]
+            results_no_walk.untracked, ["untracked_file", "untracked_dir/"]
         )
 
     def test_status_crlf_mismatch(self):
@@ -2192,7 +2190,7 @@ class StatusTests(PorcelainTestCase):
             f.write("foo")
 
         self.assertEqual(
-            {"dir" + os.path.sep},
+            {"dir/"},
             set(
                 porcelain.get_untracked_paths(
                     self.repo.path, self.repo.path, self.repo.open_index(), walk=False
@@ -2200,8 +2198,7 @@ class StatusTests(PorcelainTestCase):
             ),
         )
         self.assertEqual(
-            set([os.path.join("dir", "file"),
-                 os.path.join("dir", "subdir", "subfile")]),
+            set(["dir/file", "dir/subdir/subfile"]),
             set(
                 porcelain.get_untracked_paths(
                     self.repo.path, self.repo.path, self.repo.open_index(), walk=True