Attach (recommended) or Link to PDF file here:
[1.pdf.lin (1).pdf](https://github.com/mozilla/pdf.js/files/5780764/1.pdf.lin.1.pdf)

Configuration:
- Web browser and its version: FireFox 84.0 
- Operating system and its version: macOS 10.15.7
- PDF.js version: 2.7.262
- Is a browser extension: No

Steps to reproduce the problem:
1. Open the PDF with pdf.js.
2. Found the text of this PDF disappeared.

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/18492951/103877578-3d9da400-5110-11eb-8d84-4edd9aa1298b.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/18492951/103877735-6d4cac00-5110-11eb-9e76-7f3d9330086b.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

);
          }
        });
        return new TUncdeMap(tUncde);
      });
    }
     The vewer' chce, jut ue an dentty map.
    return Prme.relve(
      new IdenttyTUncdeMap(prperte.frtChar, prperte.latChar)
    );
  }
  readTUncde(tUncde) {
    var cmapObj = tUncde;
    f (Name(cmapObj)) {
      return CMapFactry.create({
        encdng: cmapObj,
        fetchBultInCMap: th._fetchBultInCMapBund,
        ueCMap: null,
      }).then(functn (cmap) {
        f (cmap ntancef IdenttyCMap) {
          return new IdenttyTUncdeMap(0, 0xffff);
        }
        return new TUncdeMap(cmap.getMap());
      });
    } ele f (Stream(cmapObj)) {
      return CMapFactry.create({
        encdng: cmapObj,
        fetchBultInCMap: th._fetchBultInCMapBund,
        ueCMap: null,
      }).then(