Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Chrome 63.0.3239.132 
- Operating system and its version: Windows 10
- PDF.js version: using your official demo project
- Is a browser extension: No

Steps to reproduce the problem:
1.  Just load attached pdf
2.

What is the expected behavior? (add screenshot)
[E-WG18_105147.pdf](https://github.com/mozilla/pdf.js/files/1634833/E-WG18_105147.pdf)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/29802177/34986271-3ca71a5c-fab7-11e7-95e8-1739dda3cd04.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

source,
      sourceStart,
      sourceEnd,
      dest,
      destStart,
      hintsValid
    ) {
      const glyphProfile = {
        length: 0,
        sizeOfInstructions: 0,
      };
      if (sourceEnd - sourceStart <= 12) {
        
        return glyphProfile;
      }
      const glyf = source.subarray(sourceStart, sourceEnd);
      let contoursCount = signedInt16(glyf[0], glyf[1]);
      if (contoursCount < 0) {
        
        contoursCount = -1;
        writeSignedInt16(glyf, 0, contoursCount);
        
        dest.set(glyf, destStart);
        glyphProfile.length = glyf.length;
        return glyphProfile;
      }
      let i,