DecoratorSpecificationDescriptor produces inconsistent resolution orders

[jamadden]

This is the same issue that was corrected in zope.container in zopefoundation/zope.container@1523b1c

This bites the zope.location tests (test_instance_conforms_to_ILocation (zope.location.tests.test_location.LocationPyProxyTests)) when run in strict IRO mode.

In fact, with an extension point to allow zope.container to replace the exact call to getProxiedObject with its own version, zope.container could/should be refactored to use this fixed version, since it has a hard dependency on zope.proxy.