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
buffers.push(currentBuf.join(""));
              currentBuf.length = 0;
            }
            const charCodeLength = this.cMap
              ? this.cMap.getCharCodeLength(charCode)
              : 1;
            for (let j = charCodeLength - 1; j >= 0; j--) {
              currentBuf.push(
                String.fromCharCode((charCode >> (8 * j)) & 0xff)
              );
            }
            continue;
          }
        }
        
        if (!hasCurrentBufErrors()) {
          buffers.push(currentBuf.join(""));
          currentBuf.length = 0;
        }
        currentBuf.push(String.fromCodePoint(unicode));
      }
      buffers.push(currentBuf.join(""));
      return buffers;
    },
  };
  return Font;
})();
var ErrorFont = (function ErrorFontClosure() {
  
  function ErrorFont(error) {