tests: bfd - move test_poll_response to EXTENDED_TESTS

  test_bfd.BFD4TestCase.test_poll_response providing
  inconsistent results is the per-patch tests.

Type: test

Change-Id: I8f1864511526fd330a7da1abfa19be3f565c683a
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/test/test_bfd.py b/test/test_bfd.py
index 7d87a92..6dc58b9 100644
--- a/test/test_bfd.py
+++ b/test/test_bfd.py
@@ -1039,6 +1039,8 @@
         self.assertNotIn("P", p.sprintf("%BFD.flags%"),
                          "Poll bit set in BFD packet")
 
+    # returning inconsistent results requiring retries in per-patch tests
+    @unittest.skipUnless(running_extended_tests, "part of extended tests")
     def test_poll_response(self):
         """ test correct response to control frame with poll bit set """
         bfd_session_up(self)