Attach (recommended) or Link to PDF file here:
[test.pdf](https://github.com/mozilla/pdf.js/files/6715502/test.pdf)

Configuration:
- Web browser and its version: Google Chrome Version 91.0.4472.114 
- Operating system and its version: Windows 10 Enterprise
- PDF.js version: 
- Is a browser extension: yes

Steps to reproduce the problem:
1. download file
2. open file



What is the expected behavior? (add screenshot)
show symbol
![image](https://user-images.githubusercontent.com/50500976/123409847-55ca8800-d5b7-11eb-9e5b-c7f3b33c00e1.png)

What went wrong? (add screenshot)
Does not show symbol
![image](https://user-images.githubusercontent.com/50500976/123409707-274cad00-d5b7-11eb-9a64-b11dcf3cdc3f.png)
Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): Latest Version Chrome extension

(baseEncoding.length || this.differences.length)
      ) {
        for (let i = 0; i < 256; ++i) {
          if (charCodeToGlyphId[i] !== undefined) {
            continue;
          }
          const glyphName = this.differences[i] || baseEncoding[i];
          if (!glyphName) {
            continue;
          }
          const glyphId = properties.glyphNames.indexOf(glyphName);
          if (glyphId > 0 && hasGlyph(glyphId)) {
            charCodeToGlyphId[i] = glyphId;
          }
        }
      }
    }
    if (charCodeToGlyphId.length === 0) {
      
      charCodeToGlyphId[0] = 0;
    }
    
    
    
    
    let glyphZeroId = numGlyphsOut - 1;
    if (!dupFirstEntry) {
      glyphZeroId = 0;
    }