fix issue with identity_same_worker, serialize_same_worker
fix issue with identity_same_worker, serialize_same_worker

returning local-static-object is not ok, for example:

serialize_same_worker(workerA);
...
serialize_same_worker(workerB);

the second 'same_worker' is actually same with workerA, not workerB.

alexeymarkov/RxCpp,Reactive-Extensions/RxCpp,alexeymarkov/RxCpp,ReactiveX/RxCpp,ReactiveX/RxCpp,alexeymarkov/RxCpp,Reactive-Extensions/RxCpp,ReactiveX/RxCpp,Reactive-Extensions/RxCpp