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 

codes = range[2];
      let code = codes[0];
      for (j = 1, jj = codes.length; j < jj; ++j) {
        if (codes[j] !== codes[j - 1] + 1) {
          end = range[0] + j - 1;
          format31012 +=
            string32(start) + 
            string32(end) + 
            string32(code); 
          start = end + 1;
          code = codes[j];
        }
      }
      format31012 +=
        string32(start) + 
        string32(range[1]) + 
        string32(code); 
    }
    header31012 =
      "\x00\x0C" + 
      "\x00\x00" + 
      string32(format31012.length + 16) + 
      "\x00\x00\x00\x00" + 
      string32(format31012.length / 12); 
  }
  return (
    cmap +
    "\x00\x04" + 
    string16(format314.length + 4) + 
    format314 +