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 streamBytesLength = streamBytes.length;
    var signatureLength = signature.length;
    var scanLength = streamBytesLength - signatureLength;
    var i = startIndex,
      j,
      found = false;
    while (i < scanLength) {
      j = 0;
      while (j < signatureLength && streamBytes[i + j] === signature[j]) {
        j++;
      }
      if (j >= signatureLength) {
        
        i += j;
        while (i < streamBytesLength && isWhiteSpace(streamBytes[i])) {
          i++;
        }
        found = true;
        break;
      }
      i++;
    }
    return {
      found,
      length: i,
    };
  }
  function getHeaderBlock(stream, suggestedLength) {