bpo-37999: No longer use __int__ in implicit integer conversions. (GH-15636)

Only __index__ should be used to make integer conversions lossless.
diff --git a/Lib/test/test_int.py b/Lib/test/test_int.py
index 6fdf52e..d6be64e 100644
--- a/Lib/test/test_int.py
+++ b/Lib/test/test_int.py
@@ -517,10 +517,7 @@
         self.assertIs(type(n), int)
 
         bad_int = TruncReturnsBadInt()
-        with self.assertWarns(DeprecationWarning):
-            n = int(bad_int)
-        self.assertEqual(n, 1)
-        self.assertIs(type(n), int)
+        self.assertRaises(TypeError, int, bad_int)
 
         good_int = TruncReturnsIntSubclass()
         n = int(good_int)