Update test_stop_iteration_leak

Now raises InferenceError instead of returning Uninferable. Still no
StopIteration leak.

Author: nelfin

tests/unittest_inference.py

@@ -1704,7 +1704,8 @@ def __init__(self):
         """
         ast = extract_node(code, __name__)
         expr = ast.func.expr
-        self.assertIs(next(expr.infer()), util.Uninferable)
+        with pytest.raises(exceptions.InferenceError):
+            next(expr.infer())
 
     def test_tuple_builtin_inference(self):
         code = """