Explain testSFBug532646 skip

Lib/test/test_class.py

@@ -494,7 +494,7 @@ class ClassTests(unittest.TestCase):
         self.assertRaises(TypeError, hash, C2())
 
 
-    @unittest.skip("TODO: RUSTPYTHON")
+    @unittest.skip("TODO: RUSTPYTHON, segmentation fault")
     def testSFBug532646(self):
         # Test for SF bug 532646