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):

describe("Page", function () {
    let pdfLoadingTask, pdfDocument, page;
    beforeAll(async function () {
      pdfLoadingTask = getDocument(basicApiGetDocumentParams);
      pdfDocument = await pdfLoadingTask.promise;
      page = await pdfDocument.getPage(1);
    });
    afterAll(async function () {
      await pdfLoadingTask.destroy();
    });
    it("gets page number", function () {
      expect(page.pageNumber).toEqual(1);
    });
    it("gets rotate", function () {
      expect(page.rotate).toEqual(0);
    });
    it("gets ref", function () {
      expect(page.ref).toEqual({ num: 15, gen: 0 });
    });
    it("gets userUnit", function () {
      expect(page.userUnit).toEqual(1.0);
    });
    it("gets view", function () {
      expect(page.view).toEqual([0, 0, 595.28, 841.89]);
    });
    it("gets view, with empty/invalid bounding boxes", async function () {
      const viewLoadingTask = getDocument(
        buildGetDocumentParams("boundingBox_invalid.pdf")
      );
      const pdfDoc = await viewLoadingTask.promise;