spec/resty/concurrent/timer_task: use spies instead of stubs
spec/resty/concurrent/timer_task: use spies instead of stubs

TimerTask is now built calling GC.set_metatable_gc. That method returns
an object for which type() returns "userdata". Luassert only allows
creating stubs on objects for which type() returns "table".

3scale/apicast,3scale/apicast,3scale/docker-gateway,3scale/apicast,3scale/docker-gateway,3scale/apicast