Try to reenable Flow on Windows CI

We should have more memory now

Author: gaearon

appveyor.yml

@@ -30,7 +30,7 @@ install:
 test_script:
   - node --version
   - yarn lint
-#  - yarn flow-ci (seems like we need more memory for it)
+  - yarn flow-ci
   - yarn build
   - yarn test
   - yarn prettier