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):

var toFontChar = [],
      unicode;
    for (var i = 0, ii = encoding.length; i < ii; i++) {
      unicode = getUnicodeForGlyph(encoding[i], glyphsUnicodeMap);
      if (unicode !== -1) {
        toFontChar[i] = unicode;
      }
    }
    for (var charCode in differences) {
      unicode = getUnicodeForGlyph(differences[charCode], glyphsUnicodeMap);
      if (unicode !== -1) {
        toFontChar[+charCode] = unicode;
      }
    }
    return toFontChar;
  }
  /**
   * Rebuilds the char code to glyph ID map by moving all char codes to the
   * private use area. This is done to avoid issues with various problematic
   * unicode areas where either a glyph won't be drawn or is deformed by a
   * shaper.
   * @returns {Object} Two properties:
   * 'toFontChar' - maps original char codes(the value that will be read
   * from commands such as show text) to the char codes that will be used in the
   * font that we build
   * 'charCodeToGlyphId' - maps the new font char codes to glyph ids
   */
  function adjustMapping(charCodeToGlyphId, hasGlyph, newGlyphZeroId) {