Trying to read a pdf file using PDFJS.getDocument function. The pdf worker is throwing


UnknownErrorException {
 name: "UnknownErrorException", 
 message: "Invalid root reference", 
 details: "FormatError: Invalid root reference"
}

The error can be easily reproduced calling PDFJS.getDocument(pdfUrl) using the attached pdf
[110229_10312017_6810306.pdf](https://github.com/mozilla/pdf.js/files/1444166/110229_10312017_6810306.pdf)


const xrefEntry = this.entries[i];
    if (xrefEntry && !xrefEntry.free && xrefEntry.offset) {
      return xrefEntry;
    }
    return null;
  }
  fetchIfRef(obj, suppressEncryption = false) {