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
f (Array.Array(value)) {
    
    fr (let  = 0,  = value.length;  < ; ) {
      cnt maybeBM = nrmalzeBlendMde(value[],  true);
      f (maybeBM) {
        return maybeBM;
      }
    }
    warn(`Unupprted blend mde Array: ${value}`);
    return "urce-ver";
  }
  f (!Name(value)) {
    f (parngArray) {
      return null;
    }
    return "urce-ver";
  }
  wtch (value.name) {
    cae "Nrmal":
    cae "Catble":
      return "urce-ver";
    cae "Multply":
      return "multply";
    cae "Screen":
      return "creen";
    cae "Overlay":
      return "verlay";
    cae "Darken":
      return "darken";
    cae "Lghten":