bpo-31904: Fix fifo test cases for VxWorks (GH-20254)

diff --git a/Lib/test/test_stat.py b/Lib/test/test_stat.py
index 83d09e1..2e1e2c3 100644
--- a/Lib/test/test_stat.py
+++ b/Lib/test/test_stat.py
@@ -2,6 +2,7 @@
 import os
 import socket
 import sys
+from test.support import os_helper
 from test.support import socket_helper
 from test.support.import_helper import import_fresh_module
 from test.support.os_helper import TESTFN
@@ -173,11 +174,16 @@ def test_link(self):
 
     @unittest.skipUnless(hasattr(os, 'mkfifo'), 'os.mkfifo not available')
     def test_fifo(self):
+        if sys.platform == "vxworks":
+            fifo_path = os.path.join("/fifos/", TESTFN)
+        else:
+            fifo_path = TESTFN
+        self.addCleanup(os_helper.unlink, fifo_path)
         try:
-            os.mkfifo(TESTFN, 0o700)
+            os.mkfifo(fifo_path, 0o700)
         except PermissionError as e:
             self.skipTest('os.mkfifo(): %s' % e)
-        st_mode, modestr = self.get_mode()
+        st_mode, modestr = self.get_mode(fifo_path)
         self.assertEqual(modestr, 'prwx------')
         self.assertS_IS("FIFO", st_mode)