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)


let m;
      if (
        token.startsWith("xref") &&
        (token.length === 4 || /\s/.test(token[4]))
      ) {
        position += skipUntil(buffer, position, trailerBytes);
        trailers.push(position);
        position += skipUntil(buffer, position, startxrefBytes);
      } else if ((m = objRegExp.exec(token))) {
        const num = m[1] | 0,
          gen = m[2] | 0;
        let contentLength,
          startPos = position + token.length,
          updateEntries = false;
        if (!this.entries[num]) {
          updateEntries = true;
        } else if (this.entries[num].gen === gen) {
          
          
          try {
            const parser = new Parser({
              lexer: new Lexer(stream.makeSubStream(startPos)),
            });
            parser.getObj();
            updateEntries = true;
          } catch (ex) {
            if (ex instanceof ParserEOFException) {
              warn(`indexObjects -- checking object (${token}): "${ex}".`);
            } else {