Make test_class work (but still fail) even though class.__dict__ is now a
'dictproxy' (which is a read-only non-dict mapping type that can't be passed
to exec.)

The failures the test finds are behavioural differences between old- and
new-style classes that may or may not be intended.
diff --git a/Lib/test/test_class.py b/Lib/test/test_class.py
index b8b4cab..601b8b4 100644
--- a/Lib/test/test_class.py
+++ b/Lib/test/test_class.py
@@ -115,9 +115,12 @@
     print "__%(method)s__:", args
 """
 
+d = {}
 for method in testmeths:
-    exec method_template % locals() in AllTests.__dict__
-
+    exec method_template % locals() in d
+for k in d:
+    setattr(AllTests, k, d[k])
+del d, k
 del method, method_template
 
 # this also tests __init__ of course.