Test whether libdefs contain all exports from orbit-compnents/src/index.js

[silvenon]

The problem is it's possible to forget to add a new export to orbit-components/src/index.js.flow and orbit-components/src/index.d.ts (that goes for all libdefs, but one step at a time). It would be great if we could test in CI whether they contain all of the exports. This can be done by parsing both files and checking their AST, you can use AST explorer for this. It's probably enough to use Babel parser for both files.