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 tables = Object.create(null);
      tables["OS/2"] = null;
      tables.cmap = null;
      tables.head = null;
      tables.hhea = null;
      tables.hmtx = null;
      tables.maxp = null;
      tables.name = null;
      tables.post = null;
      for (let i = 0; i < numTables; i++) {
        const table = readTableEntry(file);
        if (!VALID_TABLES.includes(table.tag)) {
          continue; 
        }
        if (table.length === 0) {
          continue; 
        }
        tables[table.tag] = table;
      }
      return tables;
    }
    function readTableEntry(file) {