goma: back to build-provided client and disable oauth2

scripts/slave/recipes/android/builder.expected/full_chromium_perf_Android_Builder.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "chromium.perf",
       "--builder",
       "Android Builder",
@@ skipping 169 matching lines @@
       "--src-dir",
       "[SLAVE_BUILD]/src",
       "--goma-cache-dir",
       "[GOMA_CACHE]",
       "--build-tool",
       "ninja",
       "--compiler",
       "goma",
       "--goma-jsonstatus",
       "/path/to/tmp/json",
-      "--goma-service-account-json-file",
-      "/creds/service_accounts/service-account-goma-client.json",
       "--goma-dir",
       "[BUILD]/goma",
       "--",
       "android_tools",
       "cc_perftests",
       "chrome_public_apk",
       "gpu_perftests",
       "push_apps_to_background_apk",
       "system_webview_apk",
       "system_webview_shell_apk"
@@ skipping 71 matching lines @@
     "~followup_annotations": [
       "@@@STEP_TEXT@WebView Nexus5 Perf (1)<br />WebView Nexus5X Perf (1)<br />WebView Nexus5X Perf (2)@@@"
     ]
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]