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 

}
        
        
        forcePostTable = true;
      } else {
        
        
        
        
        
        
        
        
        
        
        for (let i = 0; i < cmapMappingsLength; ++i) {
          let charCode = cmapMappings[i].charCode;
          if (
            cmapPlatformId === 3 &&
            charCode >= 0xf000 &&
            charCode <= 0xf0ff
          ) {
            charCode &= 0xff;
          }
          charCodeToGlyphId[charCode] = cmapMappings[i].glyphId;
        }
      }
      
      if (
        properties.glyphNames &&