[swarming/api] Add text in to indicate whether a shard is failing

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--spec",
       "cache_dir = '[GIT_CACHE]'\nsolutions = [{'deps_file': '.DEPS.git', 'managed': True, 'name': 'src', 'url': 'https://chromium.googlesource.com/chromium/src.git'}]",
       "--patch_root",
       "src",
@@ skipping 499 matching lines @@
       "/path/to/tmp/"
     ],
     "env": {
       "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "telemetry_gpu_unittests on Intel GPU on Mac on Mac-10.10",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@outdir_json@{@@@",
       "@@@STEP_LOG_LINE@outdir_json@  \"0/output.json\": \"{\\\"successes\\\": [\\\"test1.Test1\\\", \\\"test2.Test2\\\"], \\\"failures\\\": [], \\\"valid\\\": true, \\\"times\\\": {\\\"test2.Test2\\\": 0.1, \\\"test1.Test1\\\": 0.1}}\", @@@",
-      "@@@STEP_LOG_LINE@outdir_json@  \"summary.json\": \"{\\\"shards\\\": [{\\\"internal_failure\\\": false, \\\"failure\\\": false}]}\"@@@",
+      "@@@STEP_LOG_LINE@outdir_json@  \"summary.json\": \"{\\\"shards\\\": [{\\\"internal_failure\\\": false, \\\"failure\\\": false, \\\"exit_code\\\": 0}]}\"@@@",
       "@@@STEP_LOG_LINE@outdir_json@}@@@",
       "@@@STEP_LOG_END@outdir_json@@@",
       "@@@STEP_LINK@shard #0@https://chromium-swarm.appspot.com/user/task/10000@@@"
     ]
   },
   {
     "cmd": [
       "python",
       "-u",
       "[SLAVE_BUILD]/src/tools/swarming_client/swarming.py",
       "collect",
       "--swarming",
       "https://chromium-swarm.appspot.com",
       "--decorate",
       "--print-status-updates",
       "--json",
       "{\"base_task_name\": \"telemetry_gpu_unittests on NVIDIA GPU on Mac Retina/Mac-10.9/eeeeeeeeee/Mac10.9 Tests/571\", \"tasks\": {\"telemetry_gpu_unittests on NVIDIA GPU on Mac Retina/Mac-10.9/eeeeeeeeee/Mac10.9 Tests/571\": {\"shard_index\": 0, \"task_id\": \"10000\", \"view_url\": \"https://chromium-swarm.appspot.com/user/task/10000\"}}}",
       "--task-output-dir",
       "/path/to/tmp/"
     ],
     "env": {
       "FORCE_MAC_TOOLCHAIN": "1",
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "telemetry_gpu_unittests on NVIDIA GPU on Mac Retina on Mac-10.9",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@outdir_json@{@@@",
       "@@@STEP_LOG_LINE@outdir_json@  \"0/output.json\": \"{\\\"successes\\\": [\\\"test1.Test1\\\", \\\"test2.Test2\\\"], \\\"failures\\\": [], \\\"valid\\\": true, \\\"times\\\": {\\\"test2.Test2\\\": 0.1, \\\"test1.Test1\\\": 0.1}}\", @@@",
-      "@@@STEP_LOG_LINE@outdir_json@  \"summary.json\": \"{\\\"shards\\\": [{\\\"internal_failure\\\": false, \\\"failure\\\": false}]}\"@@@",
+      "@@@STEP_LOG_LINE@outdir_json@  \"summary.json\": \"{\\\"shards\\\": [{\\\"internal_failure\\\": false, \\\"failure\\\": false, \\\"exit_code\\\": 0}]}\"@@@",
       "@@@STEP_LOG_LINE@outdir_json@}@@@",
       "@@@STEP_LOG_END@outdir_json@@@",
       "@@@STEP_LINK@shard #0@https://chromium-swarm.appspot.com/user/task/10000@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]