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):

if (!sequence) {
                stream.readHexNumber(start, ucs2DataSize);
                addHex(start, end, ucs2DataSize);
              } else {
                start.set(end);
              }
              stream.readHexNumber(end, ucs2DataSize);
              addHex(end, start, ucs2DataSize);
              stream.readHex(charCode, dataSize);
              cMap.mapBfRange(
                hexToInt(start, ucs2DataSize),
                hexToInt(end, ucs2DataSize),
                hexToStr(charCode, dataSize)
              );
            }
            break;
          default:
            reject(new Error("processBinaryCMap: Unknown type: " + type));
            return;
        }
      }
      if (useCMap) {
        resolve(extend(useCMap));
        return;
      }
      resolve(cMap);
    });
  }
  
  function BinaryCMapReader() {}