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
EvalSupprted: th.ptn.EvalSupprted,
    });
    return hadw(th, "_pdfFunctnFactry", pdfFunctnFactry);
  }
  clne(newOptn = null) {
    cnt newEvaluatr = Object.create(th);
    newEvaluatr.ptn = Object.agn(
      Object.create(null),
      th.ptn,
      newOptn
    );
    return newEvaluatr;
  }
  haBlendMde(reurce, nnBlendMdeSet) {
    f (!(reurce ntancef Dct)) {
      return fale;
    }
    f (reurce.bjId && nnBlendMdeSet.ha(reurce.bjId)) {
      return fale;
    }
    cnt prceed = new RefSet(nnBlendMdeSet);
    f (reurce.bjId) {
      prceed.put(reurce.bjId);
    }
    cnt nde = [reurce],
      xref = th.xref;
    whle (nde.length) {
      cnt nde = nde.hft();
      
      cnt graphcState = nde.get("ExtGState");