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 firstEntryLength = itemDecode(locaData, itemSize);
        if (newGlyfData.length > firstEntryLength + writeOffset) {
          glyf.data = newGlyfData.subarray(0, firstEntryLength + writeOffset);
        } else {
          glyf.data = new Uint8Array(firstEntryLength + writeOffset);
          glyf.data.set(newGlyfData.subarray(0, writeOffset));
        }
        glyf.data.set(newGlyfData.subarray(0, firstEntryLength), writeOffset);
        itemEncode(
          loca.data,
          locaData.length - itemSize,
          writeOffset + firstEntryLength
        );
      } else {
        glyf.data = newGlyfData.subarray(0, writeOffset);
      }
      return {
        missingGlyphs,
        maxSizeOfInstructions,
      };
    }
    function readPostScriptTable(post, propertiesObj, maxpNumGlyphs) {
      const start = (font.start ? font.start : 0) + post.offset;
      font.pos = start;
      const length = post.length,
        end = start + length;
      const version = font.getInt32();