Link to PDF file (or attach file here):
[pages4.pdf](https://github.com/mozilla/pdf.js/files/1128300/pages4.pdf)

Configuration:
- Web browser and its version: Firefox 54
- Operating system and its version: Win 10
- PDF.js version: 1.8.522
- Is an extension: no

What is the expected behavior? (add screenshot)
![chrome1-1 1](https://user-images.githubusercontent.com/146436/27918380-2f74512a-6245-11e7-8525-d0038fa6c2e8.jpg)
![chrome1-2 1](https://user-images.githubusercontent.com/146436/27918425-54f8e47e-6245-11e7-9bff-127f79ad0511.jpg)


What went wrong? (add screenshot)
![screenshot from 2017-07-06 12-10-30](https://user-images.githubusercontent.com/146436/27918442-5d57624e-6245-11e7-9436-5ba31cc8bd1a.png)
![screenshot from 2017-07-06 12-10-44](https://user-images.githubusercontent.com/146436/27918454-63b486da-6245-11e7-9eb5-c03aa5c40943.png)



ctx.stroke();
        ctx.restore();
      } else {
        const lineWidth = this.getSinglePixelWidth();
        if (lineWidth < 0 && -lineWidth >= this.current.lineWidth) {
          
          
          ctx.save();
          ctx.resetTransform();
          ctx.lineWidth = Math.round(this._combinedScaleFactor);
          ctx.stroke();
          ctx.restore();
        } else {
          
          ctx.lineWidth = Math.max(lineWidth, this.current.lineWidth);
          ctx.stroke();
        }
      }
    }
    if (consumePath) {
      this.consumePath();
    }
    
    ctx.globalAlpha = this.current.fillAlpha;
  }
  closeStroke() {
    this.closePath();
    this.stroke();
  }
  fill(consumePath) {