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):

fileSpecDict.set("Desc", "");
      fileSpecDict.set("EF", embeddedFileDict);
      fileSpecDict.set("UF", "Test.txt");
      const fileAttachmentRef = Ref.get(20, 0);
      const fileAttachmentDict = new Dict();
      fileAttachmentDict.set("Type", Name.get("Annot"));
      fileAttachmentDict.set("Subtype", Name.get("FileAttachment"));
      fileAttachmentDict.set("FS", fileSpecRef);
      fileAttachmentDict.set("T", "Topic");
      fileAttachmentDict.set("Contents", "Test.txt");
      const xref = new XRefMock([
        { ref: fileStreamRef, data: fileStreamDict },
        { ref: fileSpecRef, data: fileSpecDict },
        { ref: fileAttachmentRef, data: fileAttachmentDict },
      ]);
      embeddedFileDict.assignXref(xref);
      fileSpecDict.assignXref(xref);
      fileAttachmentDict.assignXref(xref);
      AnnotationFactory.create(
        xref,
        fileAttachmentRef,
        pdfManagerMock,
        idFactoryMock
      ).then(({ data }) => {
        ta.annotationType).toEqual(AnnotationType.FILEATTACHMENT);
        ta.file.filename).toEqual("Test.txt");
        ta.file.content).toEqual(stringToBytes("Test attachment"));
        done();
      }, done.fail);
    });