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):

funcId = stack.pop();
          ttContext.functionsDefined[funcId] = { data, i };
        } else if (op === 0x2d) {
          
          if (inFDEF) {
            inFDEF = false;
            lastEndf = i;
          } else {
            pc = callstack.pop();
            if (!pc) {
              warn("TT: ENDF bad stack");
              ttContext.hintsValid = false;
              return;
            }
            funcId = functionsCalled.pop();
            data = pc.data;
            i = pc.i;
            ttContext.functionsStackDeltas[funcId] = stack.length - pc.stackTop;
          }
        } else if (op === 0x89) {
          
          if (inFDEF || inELSE) {
            warn("TT: nested IDEFs not allowed");
            tooComplexToFollowFunctions = true;
          }
          inFDEF = true;
          
          lastDeff = i;
        } else if (op === 0x58) {