tests: Check for dirty yarn.lock (#29728)

Author: ascorbic

.circleci/config.yml

@@ -179,6 +179,7 @@ jobs:
       - <<: *install_node_modules
       - <<: *persist_cache
       - run: yarn bootstrap -- concurrency=2
+      - run: git status yarn.lock -s | grep "M yarn.lock" && echo "yarn.lock is dirty. Please ensure changes have been committed" && exit 1
       # Persist the workspace again with all packages already built
       - persist_to_workspace:
           root: ./