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 

constructor(name, file, properties) {
    this.name = name;
    this.psName = null;
    this.mimetype = null;
    this.disableFontFace = false;
    this.loadedName = properties.loadedName;
    this.isType3Font = properties.isType3Font;
    this.missingFile = false;
    this.cssFontInfo = properties.cssFontInfo;
    this._charsCache = Object.create(null);
    this._glyphCache = Object.create(null);
    this.isSerifFont = !!(properties.flags & FontFlags.Serif);
    this.isSymbolicFont = !!(properties.flags & FontFlags.Symbolic);
    this.isMonospace = !!(properties.flags & FontFlags.FixedPitch);
    let type = properties.type;
    let subtype = properties.subtype;
    this.type = type;
    this.subtype = subtype;
    let fallbackName = "sans-serif";
    if (this.isMonospace) {
      fallbackName = "monospace";
    } else if (this.isSerifFont) {
      fallbackName = "serif";
    }
    this.fallbackName = fallbackName;
    this.differences = properties.differences;
    this.widths = properties.widths;
    this.defaultWidth = properties.defaultWidth;
    this.composite = properties.composite;
    this.cMap = properties.cMap;