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 

const GlyphMapForStandardFonts = getGlyphMapForStandardFonts();
          for (const charCode in GlyphMapForStandardFonts) {
            map[+charCode] = GlyphMapForStandardFonts[charCode];
          }
        }
      }
      this.toFontChar = map;
    }
    amendFallbackToUnicode(properties);
    this.loadedName = fontName.split("-")[0];
    this.fontType = getFontType(type, subtype, properties.isStandardFont);
  }
  checkAndRepair(name, font, properties) {
    const VALID_TABLES = [
      "OS/2",
      "cmap",
      "head",
      "hhea",
      "hmtx",
      "maxp",
      "name",
      "post",
      "loca",
      "glyf",
      "fpgm",
      "prep",
      "cvt ",
      "CFF ",
    ];
    function readTables(file, numTables) {