Attach (recommended) or Link to PDF file here:
https://www.nta.go.jp/taxes/tetsuzuki/shinsei/annai/joyaku/annai/pdf2/250.pdf

Configuration:
- Web browser and its version: Firefox 81.0a1
- Operating system and its version: Debian 5.6.7-1
- PDF.js version: latest in Firefox nightly
- Is a browser extension: No

Steps to reproduce the problem:
1. Open the pdf and paste the following text "本 店 又 は 主 た る 事 務 所 の 所 在 地" in "Full name" and in "Domicile and residence" textfields
2. Print or Save the pdf 

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/91207547-30f05480-e709-11ea-9abd-2af5d970dc46.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/91207663-69902e00-e709-11ea-8a1d-1ddd30cf0621.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

buffer.push(entity);
        start = i + 1;
      }
    } else {
      if (start < i) {
        buffer.push(str.substring(start, i));
      }
      buffer.push(`&#x${char.toString(16).toUpperCase()};`);
      if (char > 0xd7ff && (char < 0xe000 || char > 0xfffd)) {
        
        i++;
      }
      start = i + 1;
    }
  }
  if (buffer.length === 0) {
    return str;
  }
  if (start < str.length) {
    buffer.push(str.substring(start, str.length));
  }
  return buffer.join("");
}
export {
  BaseException,
  FONT_IDENTITY_MATRIX,
  IDENTITY_MATRIX,
  OPS,
  VerbosityLevel,
  UNSUPPORTED_FEATURES,