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):

} else {
          affectedBoundary.x2New = maxXNew;
        }
      } else if (affectedBoundary.x2New > maxXNew) {
        
        affectedBoundary.x2New = Math.max(maxXNew, affectedBoundary.x2);
      }
    }
    
    const changedHorizon = [];
    let lastBoundary = null;
    for (q = i; q <= j; q++) {
      horizonPart = horizon[q];
      affectedBoundary = horizonPart.boundary;
      
      const useBoundary =
        affectedBoundary.x2 > boundary.x2 ? affectedBoundary : boundary;
      if (lastBoundary === useBoundary) {
        
        changedHorizon[changedHorizon.length - 1].end = horizonPart.end;
      } else {
        changedHorizon.push({
          start: horizonPart.start,
          end: horizonPart.end,
          boundary: useBoundary,
        });
        lastBoundary = useBoundary;
      }
    }
    if (horizon[i].start < boundary.y1) {