Add json test results format support for SwarmingIsolatedScriptTest

scripts/slave/recipes/chromium.expected/dynamic_swarmed_sharded_passed_isolated_script_test.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 405 matching lines @@
       "--task-output-dir",
       "/path/to/tmp/"
     ],
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "telemetry_gpu_unittests on Ubuntu-12.04",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@outdir_json@{@@@",
       "@@@STEP_LOG_LINE@outdir_json@  \"0/chartjson-output.json\": \"{\\\"dummy\\\": \\\"dummy0\\\", \\\"enabled\\\": true, \\\"charts\\\": {\\\"entry2\\\": \\\"chart2\\\", \\\"entry1\\\": \\\"chart1\\\"}}\", @@@",
-      "@@@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@  \"0/output.json\": \"{\\\"tests\\\": {\\\"test1\\\": {\\\"Test1\\\": {\\\"expected\\\": \\\"PASS\\\", \\\"actual\\\": \\\"PASS\\\"}, \\\"Test2\\\": {\\\"expected\\\": \\\"PASS TIMEOUT\\\", \\\"actual\\\": \\\"TIMEOUT\\\"}}, \\\"test_common\\\": {\\\"Test1\\\": {\\\"expected\\\": \\\"PASS\\\", \\\"actual\\\": \\\"FAIL FAIL PASS\\\"}}}, \\\"interrupted\\\": false, \\\"path_delimiter\\\": \\\".\\\", \\\"version\\\": 3, \\\"seconds_since_epoch\\\": 14000000, \\\"num_failures_by_type\\\": {\\\"FAIL\\\": 0, \\\"PASS\\\": 2}}\", @@@",
       "@@@STEP_LOG_LINE@outdir_json@  \"1/chartjson-output.json\": \"{\\\"dummy\\\": \\\"dummy1\\\", \\\"enabled\\\": true, \\\"charts\\\": {\\\"entry3\\\": \\\"chart3\\\", \\\"entry4\\\": \\\"chart4\\\"}}\", @@@",
-      "@@@STEP_LOG_LINE@outdir_json@  \"1/output.json\": \"{\\\"successes\\\": [\\\"test3.Test3\\\", \\\"test4.Test4\\\"], \\\"failures\\\": [], \\\"valid\\\": true, \\\"times\\\": {\\\"test3.Test3\\\": 0.1, \\\"test4.Test4\\\": 0.1}}\", @@@",
+      "@@@STEP_LOG_LINE@outdir_json@  \"1/output.json\": \"{\\\"tests\\\": {\\\"test3\\\": {\\\"Test3\\\": {\\\"expected\\\": \\\"PASS\\\", \\\"actual\\\": \\\"PASS\\\"}, \\\"Test4\\\": {\\\"expected\\\": \\\"PASS TIMEOUT\\\", \\\"actual\\\": \\\"TIMEOUT\\\"}}, \\\"test_common\\\": {\\\"Test3\\\": {\\\"expected\\\": \\\"PASS\\\", \\\"actual\\\": \\\"FAIL FAIL PASS\\\"}}}, \\\"interrupted\\\": false, \\\"path_delimiter\\\": \\\".\\\", \\\"version\\\": 3, \\\"seconds_since_epoch\\\": 14000001, \\\"num_failures_by_type\\\": {\\\"FAIL\\\": 0, \\\"PASS\\\": 2}}\", @@@",
       "@@@STEP_LOG_LINE@outdir_json@  \"summary.json\": \"{\\\"shards\\\": [{\\\"internal_failure\\\": false, \\\"failure\\\": false, \\\"exit_code\\\": \\\"0\\\"}, {\\\"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@@@",
       "@@@STEP_LINK@shard #1@https://chromium-swarm.appspot.com/user/task/10100@@@"
     ]
   },
   {
     "cmd": [
       "python",
@@ skipping 26 matching lines @@
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "Upload Perf Dashboard Results"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]