Revert "Adjust enum reprs for Python 3.10" (#8896)

This reverts commit 710446420c.

The change was reverted in Python 3.10.0b4:

https://mail.python.org/archives/list/python-dev@python.org/message/LSTMFAPSPD3BGZ4D6HQFODXZVB3PLYKF/

testing/python/metafunc.py

@@ -448,10 +448,7 @@ class TestMetafunc:
         enum = pytest.importorskip("enum")
         e = enum.Enum("Foo", "one, two")
         result = idmaker(("a", "b"), [pytest.param(e.one, e.two)])
-        if sys.version_info[:2] >= (3, 10):
-            assert result == ["one-two"]
-        else:
-            assert result == ["Foo.one-Foo.two"]
+        assert result == ["Foo.one-Foo.two"]
 
     def test_idmaker_idfn(self) -> None:
         """#351"""