Revert "build: remove diagnose_goma step to stop leaks"

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

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "chromium.fyi",
       "--builder",
       "Chromium Linux Goma Canary",
@@ skipping 272 matching lines @@
     "env": {
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "compile",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@json.output (invalid)@null@@@",
       "@@@STEP_LOG_END@json.output (invalid)@@@"
     ]
   },
   {
+    "cmd": [
+      "python",
+      "-u",
+      "[BUILD]/goma/diagnose_goma_log.py"
+    ],
+    "cwd": "[SLAVE_BUILD]",
+    "name": "diagnose_goma"
+  },
+  {
     "allow_subannotations": true,
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]/scripts/slave/runtest.py",
       "--target",
       "Release",
       "--xvfb",
       "--factory-properties",
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"build_data_dir\": \"[ROOT]/build_data_dir\", \"buildername\": \"Chromium Linux Goma Canary\", \"buildnumber\": 571, \"mastername\": \"chromium.fyi\", \"parent_buildername\": null, \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}",
@@ skipping 41 matching lines @@
       "GOMA_SERVICE_ACCOUNT_JSON_FILE": "/creds/service_accounts/service-account-goma-client.json"
     },
     "name": "content_unittests"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]