send user defined options from the current query

send user defined options from the current query

Revised the means by which the
:attr:`_orm.ORMExecuteState.user_defined_options` accessor receives
:class:`_orm.UserDefinedOption` and related option objects from the
context, with particular emphasis on the "selectinload" on the loader
strategy where this previously was not working; other strategies did not
have this problem. The objects that are associated with the current query
being executed, and not that of a query being cached, are now propagated
unconditionally. This essentially separates them out from the "loader
strategy" options which are explicitly associated with the compiled state
of a query and need to be used in relation to the cached query.

The effect of this fix is that a user-defined option, such as those used
by the dogpile.caching example as well as for other recipes such as
defining a "shard id" for the horizontal sharing extension, will be
correctly propagated to eager and lazy loaders regardless of whether
a cached query was ultimately invoked.

Fixes: #6887
Change-Id: Ieaae5b01c85de26ea732ebd625e6e5823a470492