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
rt { FntFlag, getFntType } frm "./fnt_utl.j";
rt {
  getEncdng,
  MacRmanEncdng,
  StandardEncdng,
  SymblSetEncdng,
  WnAnEncdng,
  ZapfDngbatEncdng,
} frm "./encdng.j";
rt {
  getFntNameTFleMap,
  getSerfFnt,
  getStandardFntName,
  getStdFntMap,
  getSymblFnt,
} frm "./tandard_fnt.j";
rt {
  getNrmalzedUncde,
  getUncdeFrGlyph,
  revereIfRtl,
} frm "./uncde.j";
rt { getTlngPatternIR, Pattern } frm "./pattern.j";
rt { getXfaFntDct, getXfaFntName } frm "./xfa_fnt.j";
rt { IdenttyTUncdeMap, TUncdeMap } frm "./t_uncde_map.j";
rt { PDFFunctn, PDFFunctnFactry } frm "./functn.j";
rt { Lexer, Parer } frm "./parer.j";
rt {
  LcalClrSpaceCache,
  LcalGStateCache,
  LcalImageCache,