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):

this._pdfDocument = pdfDocument;
  }
  get pagesCount() {
    return this._pdfDocument.numPages;
  }
  get page() {
    return this._page;
  }
  set page(value) {
    this._page = value;
  }
}
async function initPdfFindController(filename) {
  const loadingTask = getDocument(
    buildGetDocumentParams(filename || tracemonkeyFileName)
  );
  const pdfDocument = await loadingTask.promise;
  const eventBus = new EventBus();
  const linkService = new MockLinkService();
  linkService.setDocument(pdfDocument);
  const pdfFindController = new PDFFindController({
    linkService,
    eventBus,
  });
  pdfFindController.setDocument(pdfDocument); 
  return { eventBus, pdfFindController };
}
function testSearch({
  eventBus,
  pdfFindController,