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 

this.missingFile = true;
    
    
    const name = this.name;
    const type = this.type;
    const subtype = this.subtype;
    let fontName = normalizeFontName(name);
    const stdFontMap = getStdFontMap(),
      nonStdFontMap = getNonStdFontMap();
    const isStandardFont = !!stdFontMap[fontName];
    const isMappedToStandardFont = !!(
      nonStdFontMap[fontName] && stdFontMap[nonStdFontMap[fontName]]
    );
    fontName = stdFontMap[fontName] || nonStdFontMap[fontName] || fontName;
    this.bold = fontName.search(/bold/gi) !== -1;
    this.italic =
      fontName.search(/oblique/gi) !== -1 || fontName.search(/italic/gi) !== -1;
    
    
    this.black = name.search(/Black/g) !== -1;