user_defined_options returns memoized options

Updated the attribute :attr:`_orm.ORMExecuteState.user_defined_options` to
include options that were added to the statement before calling
:meth:`.Select.with_only_columns` or :meth:`_orm.Query.with_entities`.

Fixes: #13309
Change-Id: Ie6e3f46662542010f4d524820ae697638f36d459