push frames without context on file read errors in the parser

I think the intention on file read errors is to push the frame without context. There's a comment in the parser that says:

```
// There was an error reading the file, just push the frame and
// move on.
```

However, because `looper` was being called instead of `pendingCallback`, an error reading a file is causing rollbar to bubble the exception up through all the callbacks and never notify.