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
return Object.values(this.glyphCache);
    },
    /**
     * Encode a js string using font encoding.
     * The resulting array contains an encoded string at even positions
     * (can be empty) and a non-encoded one at odd positions.
     * @param {String} a js string.
     * @returns {Array<String>} an array of encoded strings or non-encoded ones.
     */
    encodeString(str) {
      const buffers = [];
      const currentBuf = [];
      
      
      
      
      const hasCurrentBufErrors = () => buffers.length % 2 === 1;
      for (let i = 0, ii = str.length; i < ii; i++) {
        const unicode = str.codePointAt(i);
        if (unicode > 0xd7ff && (unicode < 0xe000 || unicode > 0xfffd)) {
          
          i++;
        }
        if (this.toUnicode) {
          const char = String.fromCodePoint(unicode);
          const charCode = this.toUnicode.charCodeOf(char);
          if (charCode !== -1) {
            if (hasCurrentBufErrors()) {