Remove legacy Ray code. (#3121)

* Remove legacy Ray code.

* Fix cmake and simplify monitor.

* Fix linting

* Updates

* Fix

* Implement some methods.

* Remove more plasma manager references.

* Fix

* Linting

* Fix

* Fix

* Make sure class IDs are strings.

* Some path fixes

* Fix

* Path fixes and update arrow

* Fixes.

* linting

* Fixes

* Java fixes

* Some java fixes

* TaskLanguage -> Language

* Minor

* Fix python test and remove unused method signature.

* Fix java tests

* Fix jenkins tests

* Remove commented out code.

python/ray/workers/default_worker.py

@@ -88,10 +88,7 @@ if __name__ == "__main__":
     tempfile_services.set_temp_root(args.temp_dir)
 
     ray.worker.connect(
-        info,
-        mode=ray.WORKER_MODE,
-        use_raylet=(args.raylet_name is not None),
-        redis_password=args.redis_password)
+        info, mode=ray.WORKER_MODE, redis_password=args.redis_password)
 
     error_explanation = """
   This error is unexpected and should not have happened. Somehow a worker