[compiler] Repro for interaction b/w outlining and idx

babel-plugin-idx enforces that its 2nd argument is an arrow function, so
outlining needs to skip over lambdas that are args to idx. This PR adds
a small repro highlighting the issue.

ghstack-source-id: b4627ec552056f33090e2f7bc0536a6006d79d18
Pull Request resolved: facebook#30435