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
if (isNodeJS) {
          pending("Cannot simulate cross-origin requests in Node.js");
        }
        const params = buildGetDocumentParams(filename, options);
        const url = new URL(params.url);
        if (url.hostname === "localhost") {
          url.hostname = "127.0.0.1";
        } else if (params.url.hostname === "127.0.0.1") {
          url.hostname = "localhost";
        } else {
          pending("Can only run cross-origin test on localhost!");
        }
        params.url = url.href;
        loadingTask = getDocument(params);