correctly apply _set_binops_check_strict to AssociationProxy

correctly apply _set_binops_check_strict to AssociationProxy

Revised the set "binary" operators for the association proxy ``set()``
interface to correctly raise ``TypeError`` for invalid use of the ``|``,
``&``, ``^``, and ``-`` operators, as well as the in-place mutation
versions of these methods, to match the behavior of standard Python
``set()`` as well as SQLAlchemy ORM's "intstrumented" set implementation.

Fixes: #11349
Change-Id: I02442f8885107d115b7ecfa1ca716835a55d4db3