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
buildGetDocumentParams(filename, {
          docBaseUrl: "http://www.example.com/test/pdfs/qwerty.pdf",
        })
      );
      const docBaseUrlPromise = docBaseUrlLoadingTask.promise.then(function (
        pdfDoc
      ) {
        return pdfDoc.getPage(1).then(function (pdfPage) {
          return pdfPage.getAnnotations();
        });
      });
      const invalidDocBaseUrlLoadingTask = getDocument(
        buildGetDocumentParams(filename, {
          docBaseUrl: "qwerty.pdf",
        })
      );
      const invalidDocBaseUrlPromise =
        invalidDocBaseUrlLoadingTask.promise.then(function (pdfDoc) {
          return pdfDoc.getPage(1).then(function (pdfPage) {
            return pdfPage.getAnnotations();
          });
        });
      const [
        defaultAnnotations,
        docBaseUrlAnnotations,
        invalidDocBaseUrlAnnotations,
      ] = await Promise.all([
        defaultPromise,
        docBaseUrlPromise,
        invalidDocBaseUrlPromise,