Run yarn flags in CI (facebook#28345)

Author: eps1lon

.circleci/config.yml

@@ -97,6 +97,16 @@ jobs:
       - setup_node_modules
       - run: node ./scripts/tasks/flow-ci
 
+
+  yarn_flags:
+    docker: *docker
+    environment: *environment
+
+    steps:
+      - checkout
+      - setup_node_modules
+      - run: yarn flags
+
   scrape_warning_messages:
     docker: *docker
     environment: *environment
@@ -447,6 +457,11 @@ workflows:
   build_and_test:
     unless: << pipeline.parameters.prerelease_commit_sha >>
     jobs:
+      - yarn_flags:
+          filters:
+            branches:
+              ignore:
+                - builds/facebook-www
       - yarn_flow:
           filters:
             branches: