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
this._map = cmap;
  }
  ToUnicodeMap.prototype = {
    get length() {
      return this._map.length;
    },
    forEach(callback) {
      for (var charCode in this._map) {
        callback(charCode, this._map[charCode].charCodeAt(0));
      }
    },
    has(i) {
      return this._map[i] !== undefined;
    },
    get(i) {
      return this._map[i];
    },
    charCodeOf(value) {