Attach (recommended) or Link to PDF file here:
[chinese.pdf](https://github.com/mozilla/pdf.js/files/6404389/download.1.pdf)

Configuration:
- Web browser and its version:90.0.4430.93
- Operating system and its version: mac 10.15.5
- PDF.js version: 2.9.146
- Is a browser extension:no

Steps to reproduce the problem:
1. The Chinese in the attachment cannot be rendered

Brower ✅
![image](https://user-images.githubusercontent.com/13477114/116678074-81782a00-a9db-11eb-8719-74f48fcebc2b.png)

PDF.js ❌ [https://mozilla.github.io/pdf.js/web/viewer.html](https://mozilla.github.io/pdf.js/web/viewer.html)
![image](https://user-images.githubusercontent.com/13477114/116678212-a371ac80-a9db-11eb-847f-dd1ad7752c13.png)


What is the expected behavior? (add screenshot)
**The Chinese character can be rendered**
What went wrong? (add screenshot)
**All of the Chinese character cannot be rendered**
Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

const renderer = FontRendererFactory.create(this, SEAC_ANALYSIS_ENABLED);
    return shadow(this, "renderer", renderer);
  }
  exportData(extraProperties = false) {
    const exportDataProperties = extraProperties
      ? [...EXPORT_DATA_PROPERTIES, ...EXPORT_DATA_EXTRA_PROPERTIES]
      : EXPORT_DATA_PROPERTIES;
    const data = Object.create(null);
    let property, value;
    for (property of exportDataProperties) {
      value = this[property];
      
      if (value !== undefined) {
        data[property] = value;
      }
    }
    return data;
  }
  fallbackToSystemFont(properties) {