Add an extra test for long <-> float hash equivalence.

Lib/test/test_hash.py

@@ -35,6 +35,7 @@ class HashEqualityTestCase(unittest.TestCase):
         self.same_hash(int(-2**63), long(-2**63), float(-2**63))
         self.same_hash(int(1-2**63), long(1-2**63))
         self.same_hash(int(2**63-1), long(2**63-1))
+        self.same_hash(long(2**63), float(2**63))
 
     def test_coerced_floats(self):
         self.same_hash(long(1.23e300), float(1.23e300))