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 javaScript = this._collectJavaScript();
    return shadow(
      this,
      "javaScript",
      javaScript ? Object.values(javaScript) : null
    );
  }
  get jsActions() {
    const js = this._collectJavaScript();
    let actions = collectActions(
      this.xref,
      this._catDict,
      DocumentActionEventType
    );
    if (!actions && js) {
      actions = Object.create(null);
    }
    if (actions && js) {
      for (const [key, val] of Object.entries(js)) {
        if (key in actions) {
          actions[key].push(val);
        } else {
          actions[key] = [val];
        }
      }
    }
    return shadow(this, "jsActions", actions);
  }
  fontFallback(id, handler) {