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
var glyphNameIndexes = [];
            for (i = 0; i < numGlyphs; ++i) {
              var index = font.getUint16();
              if (index >= 32768) {
                valid = false;
                break;
              }
              glyphNameIndexes.push(index);
            }
            if (!valid) {
              break;
            }
            var customNames = [];
            var strBuf = [];
            while (font.pos < end) {
              var stringLength = font.getByte();
              strBuf.length = stringLength;
              for (i = 0; i < stringLength; ++i) {
                strBuf[i] = String.fromCharCode(font.getByte());
              }
              customNames.push(strBuf.join(""));
            }
            glyphNames = [];
            for (i = 0; i < numGlyphs; ++i) {
              var j = glyphNameIndexes[i];
              if (j < 258) {
                glyphNames.push(MacStandardGlyphOrdering[j]);
                continue;
              }
              glyphNames.push(customNames[j - 258]);