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):

}
      if (lastCharIndex < code) {
        lastCharIndex = code;
      }
      const position = getUnicodeRangeFor(code);
      if (position < 32) {
        ulUnicodeRange1 |= 1 << position;
      } else if (position < 64) {
        ulUnicodeRange2 |= 1 << (position - 32);
      } else if (position < 96) {
        ulUnicodeRange3 |= 1 << (position - 64);
      } else if (position < 123) {
        ulUnicodeRange4 |= 1 << (position - 96);
      } else {
        throw new FormatError(
          "Unicode ranges Bits > 123 are reserved for internal usage"
        );
      }
    }
    if (lastCharIndex > 0xffff) {
      
      
      lastCharIndex = 0xffff;
    }
  } else {
    
    firstCharIndex = 0;
    lastCharIndex = 255;
  }
  const bbox = properties.bbox || [0, 0, 0, 0];