Attach (recommended) or Link to PDF file here:
[Hong Kong Aircraft Engineering Company Limited_1511417616.1 2.pdf](https://github.com/mozilla/pdf.js/files/1539395/Hong.Kong.Aircraft.Engineering.Company.Limited_1511417616.1.2.pdf)


Configuration:
- Web browser and its version: Chrome: 63 
- Operating system and its version: windows and macOs
- PDF.js version: 2.0.185
- Is a browser extension: No

Steps to reproduce the problem:
1. Upload the above PDF and search for "article 1"
2. PDF.js showing only **2** match But actually **4** times available.   

What is the expected behavior? (add screenshot)

![screen shot 2017-12-07 at 7](https://user-images.githubusercontent.com/6101789/33720106-ed404576-db88-11e7-9c19-cf6aea74e9f3.png)



What went wrong? (add screenshot)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

b.y1 = width - e.right;
    b.x2 = box.bottom;
    b.y2 = width - e.left;
    b.index = i;
    b.x1New = undefined;
    b.x2New = undefined;
  });
  expandBoundsLTR(height, bounds);
  for (const b of bounds) {
    const i = b.index;
    expanded[i].top = b.x1New;
    expanded[i].bottom = b.x2New;
  }
  return expanded;
}
function expandBoundsLTR(width, bounds) {
  
  bounds.sort(function (a, b) {
    return a.x1 - b.x1 || a.index - b.index;
  });
  
  const fakeBoundary = {
    x1: -Infinity,
    y1: -Infinity,
    x2: 0,
    y2: Infinity,
    index: -1,
    x1New: 0,
    x2New: 0,
  };