IWF-350: Sticky state execution: use previous worker instance

[longquanzheng]

In SDK, worker service will optionally take in a url of the current instance. Then state options will allow setting a flag that the state execution will try to use the same worker instance as the previous state execution. When enabled, SDK will also send over the worker url for executing the state.

This feature should be used together with the failure recovery feature— it’s possible that the instance got killed and the processing may need to be started over.