Attach (recommended) or Link to PDF file here:
[双引号不正常.pdf](https://github.com/mozilla/pdf.js/files/3533108/default.pdf)


Configuration:
- Web browser and its version:  IE11 , chrome 
- Operating system and its version:  win7
- PDF.js version:  master
- Is a browser extension: nothing 
teps to reproduce the problem:
1. viewer.html web  online preview


What is the expected behavior? (add screenshot)
Displayed in normal characters.

What went wrong? (add screenshot)
![20190823143813](https://user-images.githubusercontent.com/6269307/63571860-062e6600-c5b4-11e9-9fff-75d65cf6bade.png)

Not only the two characters I took screenshots, but also a lot of garbled Chinese punctuation. For example, the Chinese 《》 symbol. But these garbled characters only appear in some specific very old pdf files.

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):nothing 

source,
      sourceStart,
      sourceEnd,
      dest,
      destStart,
      hintsValid
    ) {
      const glyphProfile = {
        length: 0,
        sizeOfInstructions: 0,
      };
      if (sourceEnd - sourceStart <= 12) {
        
        return glyphProfile;
      }
      const glyf = source.subarray(sourceStart, sourceEnd);
      let contoursCount = signedInt16(glyf[0], glyf[1]);
      if (contoursCount < 0) {
        
        contoursCount = -1;
        writeSignedInt16(glyf, 0, contoursCount);
        
        dest.set(glyf, destStart);
        glyphProfile.length = glyf.length;
        return glyphProfile;
      }
      let i,