Revert "Avoid Memory Leak in Rollout worker"

This reverts commit c694766fad.

rl_coach/tests/graph_managers/test_basic_rl_graph_manager.py

@@ -56,6 +56,10 @@ def test_basic_rl_graph_manager_with_cartpole_dqn_and_repeated_checkpoint_restor
     # graph_manager.save_checkpoint()
     #
     # graph_manager.task_parameters.checkpoint_restore_dir = "./experiments/test/checkpoint"
+    # graph_manager.agent_params.memory.register_var('memory_backend_params',
+    #                                                MemoryBackendParameters(store_type=None,
+    #                                                                        orchestrator_type=None,
+    #                                                                        run_type=str(RunType.ROLLOUT_WORKER)))
     # while True:
     #     graph_manager.restore_checkpoint()
     #     gc.collect()