bpo-46418: [Enum] simplify `MODULE` declaration in tests (GH-30647)

diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index a0953fb..18cc2f3 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -31,7 +31,7 @@
                 ))
     return tests
 
-MODULE = ('test.test_enum', '__main__')[__name__=='__main__']
+MODULE = __name__
 SHORT_MODULE = MODULE.split('.')[-1]
 
 # for pickle tests