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
);
      expect(
        passwordNeededLoadingTask instanceof PDFDocumentLoadingTask
      ).toEqual(true);
      const result1 = passwordNeededLoadingTask.promise.then(
        function () {
          
          expect(false).toEqual(true);
          return Promise.reject(new Error("loadingTask should be rejected"));
        },
        function (data) {
          expect(data instanceof PasswordException).toEqual(true);
          expect(data.code).toEqual(PasswordResponses.NEED_PASSWORD);
          return passwordNeededLoadingTask.destroy();
        }
      );
      const passwordIncorrectLoadingTask = getDocument(
        buildGetDocumentParams(filename, {
          password: "qwerty",
        })
      );
      expect(
        passwordIncorrectLoadingTask instanceof PDFDocumentLoadingTask
      ).toEqual(true);
      const result2 = passwordIncorrectLoadingTask.promise.then(
        function () {
          
          expect(false).toEqual(true);
          return Promise.reject(new Error("loadingTask should be rejected"));
        },