Created by: gaearon
This should fix https://github.com/facebookincubator/create-react-app/issues/2144.
If the error is one of the built-in ones, we don't collapse, and show all the internal frames up to the first instance of user code. Then collapsing logic works as before.
I found the variable overwriting confusing and hard to deal with, so I tried to separate variables. Let me know if I missed some case.