[api] API deprecations and cleanups for 1.0 (internal_config and Checkpointable actor) (#10333)

* remove

* internal config updates, remove Checkpointable

* Lower object timeout default

* remove json

* Fix flaky test

* Fix unit test

python/ray/tests/test_multi_tenancy.py

@@ -1,5 +1,4 @@
 # coding: utf-8
-import json
 import os
 import sys
 
@@ -19,9 +18,7 @@ def test_initial_workers(shutdown_only):
     ray.init(
         num_cpus=1,
         include_dashboard=True,
-        _internal_config=json.dumps({
-            "enable_multi_tenancy": True
-        }))
+        _system_config={"enable_multi_tenancy": True})
     raylet = ray.nodes()[0]
     raylet_address = "{}:{}".format(raylet["NodeManagerAddress"],
                                     raylet["NodeManagerPort"])
@@ -43,11 +40,7 @@ def test_initial_workers(shutdown_only):
 # different drivers were scheduled to the same worker process, that is, tasks
 # of different jobs were not correctly isolated during execution.
 def test_multi_drivers(shutdown_only):
-    info = ray.init(
-        num_cpus=10,
-        _internal_config=json.dumps({
-            "enable_multi_tenancy": True
-        }))
+    info = ray.init(num_cpus=10, _system_config={"enable_multi_tenancy": True})
 
     driver_code = """
 import os
@@ -120,9 +113,7 @@ def test_worker_env(shutdown_only):
             "foo1": "bar1",
             "foo2": "bar2"
         }),
-        _internal_config=json.dumps({
-            "enable_multi_tenancy": True
-        }))
+        _system_config={"enable_multi_tenancy": True})
 
     @ray.remote
     def get_env(key):