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

scripts/slave/recipes/chromium.expected/full_chromium_webrtc_fyi_Win_x64_GN.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "RECIPE_PACKAGE_REPO[build]\\scripts\\slave\\kill_processes.py"
     ],
     "name": "taskkill"
   },
   {
@@ skipping 310 matching lines @@
       "--ninja-path",
       "RECIPE_PACKAGE_REPO[depot_tools]\\ninja.exe",
       "--target",
       "Release_x64",
       "--src-dir",
       "[BUILDER_CACHE]\\Win_x64_GN\\src",
       "--goma-cache-dir",
       "[GOMA_CACHE]",
       "--goma-deps-cache-dir",
       "[GOMA_DEPS_CACHE]",
-      "--build-tool",
-      "ninja",
       "--build-data-dir",
       "[ROOT]\\build_data_dir",
       "--compiler",
       "goma",
       "--goma-jsonstatus",
       "/path/to/tmp/json",
       "--goma-service-account-json-file",
       "C:\\creds\\service_accounts\\service-account-goma-client.json",
       "--goma-dir",
       "[CACHE]\\cipd\\goma",
@@ skipping 38 matching lines @@
       "{\"blamelist\": [\"cool_dev1337@chromium.org\", \"hax@chromium.org\"], \"build_data_dir\": \"[ROOT]\\\\build_data_dir\", \"buildername\": \"Win x64 GN\", \"buildnumber\": 571, \"mastername\": \"chromium.webrtc.fyi\", \"parent_buildername\": null, \"path_config\": \"kitchen\", \"recipe\": \"chromium\", \"slavename\": \"TestSlavename\", \"workdir\": \"/path/to/workdir/TestSlavename\"}"
     ],
     "name": "package build"
   },
   {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]