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 

scaleFactors[i] * signedInt16(metrics[j + 2], metrics[j + 3])
        );
        writeSignedInt16(metrics, j + 2, lsb);
      }
    }
    
    let numGlyphsOut = numGlyphs + 1;
    let dupFirstEntry = true;
    if (numGlyphsOut > 0xffff) {
      dupFirstEntry = false;
      numGlyphsOut = numGlyphs;
      warn("Not enough space in glyfs to duplicate first glyph.");
    }
    let maxFunctionDefs = 0;
    let maxSizeOfInstructions = 0;
    if (version >= 0x00010000 && tables.maxp.length >= 22) {
      
      font.pos += 8;
      const maxZones = font.getUint16();
      if (maxZones > 2) {
        
        tables.maxp.data[14] = 0;
        tables.maxp.data[15] = 2;
      }
      font.pos += 4;
      maxFunctionDefs = font.getUint16();
      font.pos += 4;
      maxSizeOfInstructions = font.getUint16();
    }
    tables.maxp.data[4] = numGlyphsOut >> 8;