Remove unlink compatibility (unused).

Author: jaraco

importlib_resources/tests/compat/py39.py

@@ -2,7 +2,6 @@
 Backward-compatability shims to support Python 3.9 and earlier.
 """
 
-import os
 import types
 
 from jaraco.collections import Projection
@@ -29,12 +28,3 @@ def from_test_support(*names):
     from test.support import os_helper  # type: ignore
 except ImportError:
     os_helper = from_test_support('temp_dir')
-
-
-try:
-    from test.support.os_helper import unlink
-except ImportError:
-    from test.support import unlink as _unlink
-
-    def unlink(target):
-        return _unlink(os.fspath(target))