Attach (recommended) or Link to PDF file here:
[test.pdf](https://github.com/mozilla/pdf.js/files/6715502/test.pdf)

Configuration:
- Web browser and its version: Google Chrome Version 91.0.4472.114 
- Operating system and its version: Windows 10 Enterprise
- PDF.js version: 
- Is a browser extension: yes

Steps to reproduce the problem:
1. download file
2. open file



What is the expected behavior? (add screenshot)
show symbol
![image](https://user-images.githubusercontent.com/50500976/123409847-55ca8800-d5b7-11eb-9e5b-c7f3b33c00e1.png)

What went wrong? (add screenshot)
Does not show symbol
![image](https://user-images.githubusercontent.com/50500976/123409707-274cad00-d5b7-11eb-9a64-b11dcf3cdc3f.png)
Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): Latest Version Chrome extension

override = override || {
    unitsPerEm: 0,
    yMax: 0,
    yMin: 0,
    ascent: 0,
    descent: 0,
  };
  let ulUnicodeRange1 = 0;
  let ulUnicodeRange2 = 0;
  let ulUnicodeRange3 = 0;
  let ulUnicodeRange4 = 0;
  let firstCharIndex = null;
  let lastCharIndex = 0;
  if (charstrings) {
    for (let code in charstrings) {
      code |= 0;
      if (firstCharIndex > code || !firstCharIndex) {
        firstCharIndex = code;