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
return loadingTask.destroy();
      });
      await Promise.all(destroyPromises);
    });
    it("should correctly render PDFs in parallel", async function () {
      let baseline1, baseline2, baseline3;
      const promiseDone = renderPDF(pdf1)
        .then(function (data1) {
          baseline1 = data1;
          return renderPDF(pdf2);
        })
        .then(function (data2) {
          baseline2 = data2;
          return renderPDF(pdf3);
        })
        .then(function (data3) {
          baseline3 = data3;
          return Promise.all([
            renderPDF(pdf1),
            renderPDF(pdf2),
            renderPDF(pdf3),
          ]);
        })
        .then(function (dataUrls) {
          expect(dataUrls[0]).toEqual(baseline1);
          expect(dataUrls[1]).toEqual(baseline2);
          expect(dataUrls[2]).toEqual(baseline3);
          return true;
        });
      await promiseDone;