Remove a lot of test references to Python 2/3.5

test/test_inference/test_mixed.py

@@ -104,10 +104,11 @@ def test_signature():
     assert s.docstring() == 'some_signature(*, bar=1)'
 
 
-@pytest.mark.skipif(sys.version_info[0:2] < (3, 5), reason="Typing was introduced in Python 3.5")
 def test_compiled_signature_annotation_string():
     import typing
-    def func(x: typing.Type, y: typing.Union[typing.Type, int]): pass
+
+    def func(x: typing.Type, y: typing.Union[typing.Type, int]):
+        pass
     func.__name__ = 'not_func'
 
     s, = jedi.Interpreter('func()', [locals()]).get_signatures(1, 5)