Revert "build: remove diagnose_goma step to stop leaks"

scripts/slave/recipe_modules/chromium_tests/api.py

Index: scripts/slave/recipe_modules/chromium_tests/api.py
diff --git a/scripts/slave/recipe_modules/chromium_tests/api.py b/scripts/slave/recipe_modules/chromium_tests/api.py
index 3fde2b046d38c56b427752a299f568288aa8b2d4..ba591a12d0d5a54c6be609978c629d3fe4949ebe 100644
--- a/scripts/slave/recipe_modules/chromium_tests/api.py
+++ b/scripts/slave/recipe_modules/chromium_tests/api.py
@@ -310,7 +310,13 @@ class ChromiumTestsApi(recipe_api.RecipeApi):
     assert isinstance(bot_db, bdb_module.BotConfigAndTestDB), \
         "bot_db argument %r was not a BotConfigAndTestDB" % (bot_db)
 
-    return bot_config.get_tests(bot_db)
+    tests, tests_including_triggered = bot_config.get_tests(bot_db)
+
+    if bot_config.get('goma_canary') or bot_config.get('goma_staging'):
+      tests.insert(0, steps.DiagnoseGomaTest())
+      tests_including_triggered.insert(0, steps.DiagnoseGomaTest())
+
+    return tests, tests_including_triggered
 
   def get_compile_targets(self, bot_config, bot_db, tests):
     assert isinstance(bot_db, bdb_module.BotConfigAndTestDB), \