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
map[+charCode] = SupplementalGlyphMapForCalibri[charCode];
          }
        }
        
        
        if (cidToGidMap) {
          for (const charCode in map) {
            const cid = map[charCode];
            if (cidToGidMap[cid] !== undefined) {
              map[+charCode] = cidToGidMap[cid];
            }
          }
        }
        var isIdentityUnicode = this.toUnicode instanceof IdentityToUnicodeMap;
        if (!isIdentityUnicode) {
          this.toUnicode.forEach(function (charCode, unicodeCharCode) {
            map[+charCode] = unicodeCharCode;
          });
        }
        this.toFontChar = map;
        this.toUnicode = new ToUnicodeMap(map);
      } else if (/Symbol/i.test(fontName)) {
        this.toFontChar = buildToFontChar(
          SymbolSetEncoding,
          getGlyphsUnicode(),
          this.differences
        );
      } else if (/Dingbats/i.test(fontName)) {
        if (/Wingdings/i.test(name)) {
          warn("Non-embedded Wingdings font, falling back to ZapfDingbats.");