Attach (recommended) or Link to PDF file here:  [test.pdf](https://akmer.aikucun.com/a94a8fe5ccb19ba61c4c0873d391e987982fbbd3_1616477914120_83.pdf)


Configuration:
- Web browser and its version: chrome 87.0.4280.88
- Operating system and its version: windows10
- PDF.js version: 2.6.347
- Is a browser extension:

Steps to reproduce the problem:
1. just open 

What is the expected behavior? (add screenshot)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/17724610/112087066-473f8f80-8bc8-11eb-8efb-56139ec42a9c.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

const dict = Object.create(null);
    if (!this.root) {
      return dict;
    }
    const xref = this.xref;
    
    const processed = new RefSet();
    processed.put(this.root);
    const queue = [this.root];
    while (queue.length > 0) {
      const obj = xref.fetchIfRef(queue.shift());
      if (!isDict(obj)) {
        continue;
      }
      if (obj.has("Kids")) {
        const kids = obj.get("Kids");
        for (let i = 0, ii = kids.length; i < ii; i++) {
          const kid = kids[i];
          if (processed.has(kid)) {
            throw new FormatError(`Duplicate entry in "${this._type}" tree.`);
          }
          queue.push(kid);
          processed.put(kid);
        }
        continue;