[wingman -> tune] Add system performance tracking (#4924)

python/ray/tune/experiment.py

@@ -87,11 +87,13 @@ class Experiment(object):
         if sync_function:
             _raise_deprecation_note(
                 "sync_function", "sync_to_driver", soft=False)
+
+        config = config or {}
         run_identifier = Experiment._register_if_needed(run)
         spec = {
             "run": run_identifier,
             "stop": stop or {},
-            "config": config or {},
+            "config": config,
             "resources_per_trial": resources_per_trial,
             "num_samples": num_samples,
             "local_dir": os.path.expanduser(local_dir or DEFAULT_RESULTS_DIR),