Updating swarming api to check for chartjson results from a finished

scripts/slave/recipes/chromium.expected/dynamic_swarmed_isolated_script_test_win_non_gpu.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 365 matching lines @@
       "--tag",
       "purpose:CI",
       "--tag",
       "purpose:post-commit",
       "--tag",
       "slavename:TestSlavename",
       "--tag",
       "stepname:telemetry_gpu_unittests on Windows",
       "eeeeeeeeeeeeeeeeeeeeeeeeeeeeee",
       "--",
-      "--isolated-script-test-output=${ISOLATED_OUTDIR}/output.json"
+      "--isolated-script-test-output=${ISOLATED_OUTDIR}/output.json",
+      "--isolated-script-test-chartjson-output=${ISOLATED_OUTDIR}/chartjson-output.json"
     ],
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
     "name": "[trigger] telemetry_gpu_unittests on Windows",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output@{@@@",
       "@@@STEP_LOG_LINE@json.output@  \"base_task_name\": \"telemetry_gpu_unittests/Windows/eeeeeeeeee/Win7 Tests (1)/571\", @@@",
       "@@@STEP_LOG_LINE@json.output@  \"tasks\": {@@@",
       "@@@STEP_LOG_LINE@json.output@    \"telemetry_gpu_unittests/Windows/eeeeeeeeee/Win7 Tests (1)/571\": {@@@",
@@ skipping 67 matching lines @@
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "C:\\creds\\service_accounts\\service-account-goma-client.json"
     },
     "name": "process_dumps"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]