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):

data[offset + 2] = (value >> 8) & 0xff;
          data[offset + 3] = value & 0xff;
        };
      } else {
        itemSize = 2;
        itemDecode = function fontItemDecode(data, offset) {
          return (data[offset] << 9) | (data[offset + 1] << 1);
        };
        itemEncode = function fontItemEncode(data, offset, value) {
          data[offset] = (value >> 9) & 0xff;
          data[offset + 1] = (value >> 1) & 0xff;
        };
      }
      
      const numGlyphsOut = dupFirstEntry ? numGlyphs + 1 : numGlyphs;
      const locaDataSize = itemSize * (1 + numGlyphsOut);
      
      const locaData = new Uint8Array(locaDataSize);
      locaData.set(loca.data.subarray(0, locaDataSize));
      loca.data = locaData;
      
      const oldGlyfData = glyf.data;
      const oldGlyfDataLength = oldGlyfData.length;
      const newGlyfData = new Uint8Array(oldGlyfDataLength);
      
      
      
      
      
      let i, j;