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):

pending("Worker is not supported in Node.js.");
      }
      const worker = new PDFWorker({ name: "test1" });
      const loadingTask = getDocument(
        buildGetDocumentParams(basicApiFileName, {
          worker,
        })
      );
      loadingTask.promise.then(function () {
        const docWorker = loadingTask._worker;
        expect(!!docWorker).toEqual(false);
        
        const messageHandlerPort = loadingTask._transport.messageHandler.comObj;
        expect(messageHandlerPort === worker.port).toEqual(true);
      });
      const destroyPromise = loadingTask.promise.then(function () {
        return loadingTask.destroy();
      });
      await destroyPromise;
      expect(worker.destroyed).toEqual(false);
      worker.destroy();
    });
    it("creates more than one worker", async function () {
      if (isNodeJS) {
        pending("Worker is not supported in Node.js.");
      }
      const worker1 = new PDFWorker({ name: "test1" });
      const worker2 = new PDFWorker({ name: "test2" });
      const worker3 = new PDFWorker({ name: "test3" });
      await Promise.all([worker1.promise, worker2.promise, worker3.promise]);