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
if (index === -1) {
          strings.add(glyphName);
        }
        charsetArray.push(glyphName);
      }
      cff.charset = new CFFCharset(false, 0, charsetArray);
      var charStringsIndex = new CFFIndex();
      charStringsIndex.add([0x8b, 0x0e]); 
      for (i = 0; i < count; i++) {
        charStringsIndex.add(glyphs[i]);
      }
      cff.charStrings = charStringsIndex;
      var privateDict = new CFFPrivateDict();
      privateDict.setByName("Subrs", null); 
      var fields = [
        "BlueValues",
        "OtherBlues",
        "FamilyBlues",
        "FamilyOtherBlues",
        "StemSnapH",
        "StemSnapV",
        "BlueShift",
        "BlueFuzz",
        "BlueScale",
        "LanguageGroup",
        "ExpansionFactor",
        "ForceBold",
        "StdHW",
        "StdVW",
      ];