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 

info(
          "Attempting to fix invalid indexToLocFormat in head table: " +
            indexToLocFormat
        );
        
        
        
        
        
        
        
        
        
        const numGlyphsPlusOne = numGlyphs + 1;
        if (locaLength === numGlyphsPlusOne << 1) {
          
          data[50] = 0;
          data[51] = 0;
        } else if (locaLength === numGlyphsPlusOne << 2) {
          
          data[50] = 0;
          data[51] = 1;
        } else {
          throw new FormatError(
            "Could not fix indexToLocFormat: " + indexToLocFormat
          );
        }
      }
    }
    function sanitizeGlyphLocations(