catch release builds pre-submit (#50515)

.cirrus.yml

@@ -569,11 +569,12 @@ task:
 
     - name: verify_binaries_codesigned-macos # macos-only
       # TODO(fujino): remove this `only_if` after https://github.com/flutter/flutter/issues/44372
-      only_if: "$CIRRUS_BRANCH == 'dev' || $CIRRUS_BRANCH == 'beta' || $CIRRUS_BRANCH == 'stable' || $CIRRUS_BRANCH =~ '.*hotfix.*'"
+      only_if: "$CIRRUS_BASE_BRANCH != 'master'"
       depends_on:
         - analyze-linux
       script:
         - ulimit -S -n 2048 # https://github.com/flutter/flutter/issues/2976
+        - ./bin/flutter precache # ensure cached binaries are present
         - dart --enable-asserts ./dev/bots/codesign.dart
 
 docker_builder: