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 

data[offset + 2] = (value >> 8) & 0xff;
          data[offset + 3] = value & 0xff;
        };
      } else {
        itemSize = 2;
        itemDecode = function fontItemDecode(data, offset) {
          return (data[offset] << 9) | (data[offset + 1] << 1);
        };
        itemEncode = function fontItemEncode(data, offset, value) {
          data[offset] = (value >> 9) & 0xff;
          data[offset + 1] = (value >> 1) & 0xff;
        };
      }
      
      const numGlyphsOut = dupFirstEntry ? numGlyphs + 1 : numGlyphs;
      const locaDataSize = itemSize * (1 + numGlyphsOut);
      
      const locaData = new Uint8Array(locaDataSize);
      locaData.set(loca.data.subarray(0, locaDataSize));
      loca.data = locaData;
      
      const oldGlyfData = glyf.data;
      const oldGlyfDataLength = oldGlyfData.length;
      const newGlyfData = new Uint8Array(oldGlyfDataLength);
      
      
      
      
      
      let i, j;