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 glyphProfile = sanitizeGlyph(
          oldGlyfData,
          locaEntries[i].offset,
          locaEntries[i].endOffset,
          newGlyfData,
          writeOffset,
          hintsValid
        );
        const newLength = glyphProfile.length;
        if (newLength === 0) {
          missingGlyphs[i] = true;
        }
        if (glyphProfile.sizeOfInstructions > maxSizeOfInstructions) {
          maxSizeOfInstructions = glyphProfile.sizeOfInstructions;
        }
        writeOffset += newLength;
        itemEncode(locaData, j, writeOffset);
      }
      if (writeOffset === 0) {
        
        
        const simpleGlyph = new Uint8Array([
          0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 49, 0,
        ]);
        for (i = 0, j = itemSize; i < numGlyphsOut; i++, j += itemSize) {
          itemEncode(locaData, j, simpleGlyph.length);
        }
        glyf.data = simpleGlyph;
      } else if (dupFirstEntry) {