Skip test as cpython_only that checks whether setattr interns the attribute or not (python#134972)

Skip test that checks whether setattr interns the attribute or not

The details of when a string is being interned or not is implementation
dependent.

Author: cfbolz

Lib/test/test_class.py

@@ -652,6 +652,7 @@ class B(A):
         a = A(hash(A.f)^(-1))
         hash(a.f)
 
+    @cpython_only
     def testSetattrWrapperNameIntern(self):
         # Issue #25794: __setattr__ should intern the attribute name
         class A: