[3.15] gh-154443: Fix test_makedev on DragonFly BSD (GH-154444) (GH-154450)

major() and minor() do not preserve NODEV on DragonFly BSD.
(cherry picked from commit 2cf8e59)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: 3 people

Lib/test/test_os/test_posix.py

@@ -822,8 +822,7 @@ def test_makedev(self):
         # a special case for NODEV, on others this is just an implementation
         # artifact.
         if (hasattr(posix, 'NODEV') and
-            sys.platform.startswith(('linux', 'macos', 'freebsd', 'dragonfly',
-                                     'sunos'))):
+            sys.platform.startswith(('linux', 'macos', 'freebsd', 'sunos'))):
             NODEV = posix.NODEV
             self.assertEqual(posix.major(NODEV), NODEV)
             self.assertEqual(posix.minor(NODEV), NODEV)