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):

const textDivProperties = this._textDivProperties.get(textDiv);
    let transform = "";
    if (textDivProperties.canvasWidth !== 0 && textDivProperties.hasText) {
      const { fontSize, fontFamily } = textDiv.style;
      
      if (
        fontSize !== this._layoutTextLastFontSize ||
        fontFamily !== this._layoutTextLastFontFamily
      ) {
        this._layoutTextCtx.font = `${fontSize} ${fontFamily}`;
        this._layoutTextLastFontSize = fontSize;
        this._layoutTextLastFontFamily = fontFamily;
      }
      
      const { width } = this._layoutTextCtx.measureText(textDiv.textContent);