Attach (recommended) or Link to PDF file here: https://github.com/tesseract-ocr/tesseract/files/947838/2.pdf

Configuration:
- Web browser and its version: N/A
- Operating system and its version: N/A
- PDF.js version: `2.9.223`, or any version after PR #13306 landed.
- Is a browser extension: N/A

Steps to reproduce the problem:
1. Open the document above, e.g. with https://mozilla.github.io/pdf.js/web/viewer.html
2. Search for "of the r"

What is the expected behavior? (add screenshot)
Correct highlighting, please see:

![correct](https://user-images.githubusercontent.com/2692120/117328223-b7158b00-ae93-11eb-805c-73718ff569b5.png)


What went wrong? (add screenshot)
Incorrect highlighting, please see:

![incorrect](https://user-images.githubusercontent.com/2692120/117328447-efb56480-ae93-11eb-8506-da9fc0eb9630.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): N/A

/cc @brendandahl 

while (i !== end && matchIdx >= iIndex + textContentItemsStr[i].length) {
        iIndex += textContentItemsStr[i].length;
        i++;
      }
      if (i === textContentItemsStr.length) {
        console.error("Could not find a matching mapping");
      }
      const match = {
        begin: {
          divIdx: i,
          offset: matchIdx - iIndex,
        },
      };
      
      matchIdx += matchesLength[m];
      
      
      while (i !== end && matchIdx > iIndex + textContentItemsStr[i].length) {
        iIndex += textContentItemsStr[i].length;
        i++;
      }
      match.end = {
        divIdx: i,
        offset: matchIdx - iIndex,
      };
      result.push(match);
    }
    return result;
  }
  _renderMatches(matches) {