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)



if (fontDirection > 0) {
      ctx.scale(textHScale, -1);
    } else {
      ctx.scale(textHScale, 1);
    }
    let lineWidth = current.lineWidth;
    let resetLineWidthToOne = false;
    const scale = current.textMatrixScale;
    if (scale === 0 || lineWidth === 0) {
      const fillStrokeMode =
        current.textRenderingMode & TextRenderingMode.FILL_STROKE_MASK;
      if (
        fillStrokeMode === TextRenderingMode.STROKE ||
        fillStrokeMode === TextRenderingMode.FILL_STROKE
      ) {
        this._cachedGetSinglePixelWidth = null;
        lineWidth = this.getSinglePixelWidth();
        resetLineWidthToOne = lineWidth < 0;
      }
    } else {
      lineWidth /= scale;
    }
    if (fontSizeScale !== 1.0) {
      ctx.scale(fontSizeScale, fontSizeScale);
      lineWidth /= fontSizeScale;
    }
    ctx.lineWidth = lineWidth;
    let x = 0,
      i;
    for (i = 0; i < glyphsLength; ++i) {