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 objBytes = new Uint8Array([111, 98, 106]);
    const xrefBytes = new Uint8Array([47, 88, 82, 101, 102]);
    
    this.entries.length = 0;
    this._cacheMap.clear();
    const stream = this.stream;
    stream.pos = 0;
    const buffer = stream.getBytes(),
      length = buffer.length;
    let position = stream.start;
    const trailers = [],
      xrefStms = [];
    while (position < length) {
      let ch = buffer[position];
      if (ch === TAB || ch === LF || ch === CR || ch === SPACE) {
        ++position;
        continue;
      }
      if (ch === PERCENT) {
        
        do {
          ++position;
          if (position >= length) {
            break;
          }
          ch = buffer[position];
        } while (ch !== LF && ch !== CR);
        continue;
      }
      const token = readToken(buffer, position);