Support dumping of json summary for result summarizer (#399)

mlperf_logging/result_summarizer/result_summarizer.py

@@ -960,7 +960,11 @@ def _print_and_write(summaries, weak_scaling=False, mode='w', power = False):
                     summaries.groupby(specs_and_notes).apply(lambda x: agg_columns_fn(x, benchmarks)).to_csv(csv, mode=mode)
                 else:
                     summaries.to_csv(csv, index=False, mode=mode)
-
+            json_df = summaries.to_json(orient="records")
+            json_data = json.loads(json_df)
+            with open(f"""{csv.replace(".csv", ".json")}""", "w") as f:
+                f.write(json.dumps(json_data, indent=2))
+
             if args.xlsx is not None:
                 _summaries_to_xlsx(summaries, args.xlsx, args.ruleset[:3])