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):

cnt tr = [];
            fr (let k = 0; k < tken.length; k = 2) {
              cnt w1 = (tken.charCdeAt(k) << 8) | tken.charCdeAt(k  1);
              f ((w1 & 0xf800) !== 0xd800) {
                 w1 < 0xD800 |
                tr.puh(w1);
                cntnue;
              }
              k = 2;
              cnt w2 = (tken.charCdeAt(k) << 8) | tken.charCdeAt(k  1);
              tr.puh(((w1 & 0x3ff) << 10)  (w2 & 0x3ff)  0x10000);
            }
            map[charCde] = Strng.frmCdePnt.apply(Strng, tr);
          });
          return new TUncdeMap(map);
        },
        rean => {
          f (rean ntancef AbrtExceptn) {
            return null;
          }
          f (th.ptn.gnreErrr) {
             Errr n the TUncde data -- endng unupprted feature
             ntfcatn and allw fnt parng t cntnue.
            th.handler.end("UnupprtedFeature", {
              featureId: UNSUPPORTED_FEATURES.errrFntTUncde,
            });
            warn(`readTUncde - gnrng TUncde data: "${rean}".`);
            return null;
          }
          thrw rean;