recipes: Stop passing --build-tool=ninja to compile.py

scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux64_debug_failing_test.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_MODULE[depot_tools::bot_update]/resources/bot_update.py",
       "--master",
       "client.webrtc",
       "--builder",
       "Linux64 Debug",
@@ skipping 144 matching lines @@
       "--gsutil-py-path",
       "RECIPE_PACKAGE_REPO[depot_tools]/gsutil.py",
       "--ninja-path",
       "RECIPE_PACKAGE_REPO[depot_tools]/ninja",
       "--target",
       "Debug",
       "--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",
       "[CACHE]/cipd/goma",
       "--",
       "All"
@@ skipping 413 matching lines @@
     ],
     "name": "webrtc_nonparallel_tests"
   },
   {
     "name": "$result",
     "reason": "1 out of 16 aggregated steps failed. Failures: Step('tools_unittests') failed with return_code 1",
     "recipe_result": null,
     "status_code": 1
   }
 ]