Summary:
Consequently, Babel won’t transform classes to their roughly equivalent
ES5 counterparts, etc.
Test Plan:
Create `src/classy.js` with `class X {}; console.log(X);`. Then, add a
build target for `classy: resolveApp("src/classy.js"),` in `paths.js`.
Use `yarn backend` and inspect the contents of `bin/classy.js`; in
particular, look at the definition of `X` (whatever the argument to
`console.log` is). Before this commit, the result will be a big
complicated mess. After this commit, it will be `class X {}`.
Note also that `yarn travis --full` passes, indicating that the two
manual tests, which call out to the utilities in `bin/`, still work.
wchargin-branch: target-node