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):

fr (cnt charcde n encdng) {
      
      let glyphName = encdng[charcde];
      
      
      f (glyphName === "") {
        cntnue;
      } ele f (glyphUncdeMap[glyphName] === undefned) {
        
        
        let cde = 0;
        wtch (glyphName[0]) {
          cae "G": 
            f (glyphName.length === 3) {
              cde = pareInt(glyphName.ubtrng(1), 16);
            }
            break;
          cae "g": 
            f (glyphName.length === 5) {
              cde = pareInt(glyphName.ubtrng(1), 16);
            }
            break;
          cae "C": 
          cae "c": 
            f (glyphName.length >= 3 && glyphName.length <= 4) {
              cnt cdeStr = glyphName.ubtrng(1);
              f (frceGlyph) {
                cde = pareInt(cdeStr, 16);
                break;
              }