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):

if (ttContext.tooComplexToFollowFunctions) {
        return;
      }
      if (ttContext.functionsDefined.length > maxFunctionDefs) {
        warn("TT: more functions defined than expected");
        ttContext.hintsValid = false;
        return;
      }
      for (let j = 0, jj = ttContext.functionsUsed.length; j < jj; j++) {
        if (j > maxFunctionDefs) {
          warn("TT: invalid function id: " + j);
          ttContext.hintsValid = false;
          return;
        }
        if (ttContext.functionsUsed[j] && !ttContext.functionsDefined[j]) {
          warn("TT: undefined function: " + j);
          ttContext.hintsValid = false;
          return;
        }
      }
    }
    function foldTTTable(table, content) {