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.fillText(character, x, y);
      }
      if (
        fillStrokeMode === TextRenderingMode.STROKE ||
        fillStrokeMode === TextRenderingMode.FILL_STROKE
      ) {
        if (resetLineWidthToOne) {
          ctx.save();
          ctx.moveTo(x, y);
          ctx.resetTransform();
          ctx.lineWidth = Math.round(this._combinedScaleFactor);
          ctx.strokeText(character, 0, 0);
          ctx.restore();
        } else {
          ctx.strokeText(character, x, y);
        }
      }
    }
    if (isAddToPathSet) {
      const paths = this.pendingTextPaths || (this.pendingTextPaths = []);
      paths.push({
        transform: ctx.mozCurrentTransform,
        x,
        y,
        fontSize,
        addToPath,
      });
    }
  }
  get isFontSubpixelAAEnabled() {