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 namesRecordCount = strings.length * platforms.length;
  let nameTable =
    "\x00\x00" + 
    string16(namesRecordCount) + 
    string16(namesRecordCount * 12 + 6); 
  
  let strOffset = 0;
  for (i = 0, ii = platforms.length; i < ii; i++) {
    const strs = names[i];
    for (j = 0, jj = strs.length; j < jj; j++) {
      str = strs[j];
      const nameRecord =
        platforms[i] + 
        encodings[i] + 
        languages[i] + 
        string16(j) + 
        string16(str.length) +
        string16(strOffset);
      nameTable += nameRecord;
      strOffset += str.length;
    }
  }
  nameTable += strings.join("") + stringsUnicode.join("");
  return nameTable;
}
/**
 * 'Font' is the class the outside world should use, it encapsulate all the font
 * decoding logics whatever type it is (assuming the font type is supported).
 */
class Font {