Moved compatibility tests to the compat package, as they're not included in CPython.

Author: jaraco

tests/test_py39compat.py tests/compat/test_py39_compat.py

@@ -2,7 +2,7 @@
 import pathlib
 import unittest
 
-from . import fixtures
+from .. import fixtures
 from importlib_metadata import (
     distribution,
     distributions,