Fix implementation dependent assertion in test_plistlib. (GH-4813) (#4815)

It is failed with an advanced optimizer.
(cherry picked from commit 0e069a1597ce6791a5f0da8329da2c446766c80e)

diff --git a/Lib/test/test_plistlib.py b/Lib/test/test_plistlib.py
index 90641a7635c0b5dd7a51144cc2e10d5afb083e32..d47c607329cd51142c9c58306facf04413c15186 100644 (file)
--- a/Lib/test/test_plistlib.py
+++ b/Lib/test/test_plistlib.py
@@ -321,7 +321,8 @@ class TestPlistlib(unittest.TestCase):
                     'second': [1, 2],
                     'third': [3, 4],
                 })
-                self.assertIsNot(pl2['first'], pl2['second'])
+                if fmt != plistlib.FMT_BINARY:
+                    self.assertIsNot(pl2['first'], pl2['second'])
 
     def test_list_members(self):
         pl = {