Attach (recommended) or Link to PDF file here:
[test.pdf](https://github.com/mozilla/pdf.js/files/6270827/test.pdf)
Configuration:
- Web browser and its version:chrome 89
- Operating system and its version:win10
- PDF.js version: 2.4/2.7/2.8 no working
- Is a browser extension: no 

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/18545199/113852392-1ae26080-97cf-11eb-9dc9-0cecf52d267b.png)

What went wrong? (add screenshot)
![1617791294(1)](https://user-images.githubusercontent.com/18545199/113852355-10c06200-97cf-11eb-8672-598750f1093a.jpg)


console this log : **FormatError: TrueType Collection does not contain "DCWGQU+CambriaMath" font** 

any solution?thanks
break;
        }
        var glyphsUnicodeMap = getGlyphsUnicode();
        var glyphUnicode = glyphsUnicodeMap[glyphName];
        
        var charcode = 0;
        if (this.composite && this.cMap.contains(glyphUnicode)) {
          charcode = this.cMap.lookup(glyphUnicode);
        }
        
        if (!charcode && this.toUnicode) {
          charcode = this.toUnicode.charCodeOf(glyphUnicode);
        }
        
        if (charcode <= 0) {
          charcode = glyphUnicode;
        }
        
        width = this.widths[charcode];
        if (width) {
          break; 
        }
      }
      width = width || this.defaultWidth;
      return shadow(this, "spaceWidth", width);
    },
    /**
     * @private
     */
    _charToGlyph(charcode, isSpace = false) {