Attach (recommended) or Link to PDF file here:
[298865.pdf](https://github.com/mozilla/pdf.js/files/2753236/298865.pdf)


Configuration:
- Web browser and its version:chrome 71.0.3578.98
- Operating system and its version:mac os 10.12.6
- PDF.js version:I use online demo in github
- Is a browser extension:no

Steps to reproduce the problem:
1. search "中华" or "电力" or so on,the highlight position is not right

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/10000986/51087378-7eff5100-178d-11e9-991a-005d77b82f31.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/10000986/51087374-6ee77180-178d-11e9-9707-281924f95fd0.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):
https://mozilla.github.io/pdf.js/web/viewer.html
for (let j = 0, jj = points.length; j < jj; j++) {
      const t = Util.applyTransform(points[j], m);
      ts[j + 0] = c && (e.left - t[0]) / c;
      ts[j + 4] = s && (e.top - t[1]) / s;
      ts[j + 8] = c && (e.right - t[0]) / c;
      ts[j + 12] = s && (e.bottom - t[1]) / s;
      ts[j + 16] = s && (e.left - t[0]) / -s;
      ts[j + 20] = c && (e.top - t[1]) / c;
      ts[j + 24] = s && (e.right - t[0]) / -s;
      ts[j + 28] = c && (e.bottom - t[1]) / c;
      ts[j + 32] = c && (e.left - t[0]) / -c;
      ts[j + 36] = s && (e.top - t[1]) / -s;
      ts[j + 40] = c && (e.right - t[0]) / -c;
      ts[j + 44] = s && (e.bottom - t[1]) / -s;
      ts[j + 48] = s && (e.left - t[0]) / s;
      ts[j + 52] = c && (e.top - t[1]) / -c;
      ts[j + 56] = s && (e.right - t[0]) / s;
      ts[j + 60] = c && (e.bottom - t[1]) / -c;
    }
    
    
    const boxScale = 1 + Math.min(Math.abs(c), Math.abs(s));
    divProperties.paddingLeft = findPositiveMin(ts, 32, 16) / boxScale;
    divProperties.paddingTop = findPositiveMin(ts, 48, 16) / boxScale;
    divProperties.paddingRight = findPositiveMin(ts, 0, 16) / boxScale;
    divProperties.paddingBottom = findPositiveMin(ts, 16, 16) / boxScale;
    task._textDivProperties.set(div, divProperties);
  }
}
function expandBounds(width, height, boxes) {