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
fileType = "TrueType";
      }
    } else if (isOpenTypeFile(file)) {
      if (composite) {
        fileType = "CIDFontType2";
      } else {
        fileType = "OpenType";
      }
    } else if (isType1File(file)) {
      if (composite) {
        fileType = "CIDFontType0";
      } else {
        fileType = type === "MMType1" ? "MMType1" : "Type1";
      }
    } else if (isCFFFile(file)) {
      if (composite) {
        fileType = "CIDFontType0";
        fileSubtype = "CIDFontType0C";
      } else {
        fileType = type === "MMType1" ? "MMType1" : "Type1";
        fileSubtype = "Type1C";
      }
    } else {
      warn("getFontFileType: Unable to detect correct font file Type/Subtype.");
      fileType = type;
      fileSubtype = subtype;
    }
    return [fileType, fileSubtype];
  }
  function buildToFontChar(encoding, glyphsUnicodeMap, differences) {