https://pdf.yt/d/BeioWriXAn-DkFcO

When searching the above pdf for the phrase 'acute' the second hit hightlights the nearby word ' especi'.  Almost certainly this is the same issue that I raised in #5667 

However, when examining the generated html you can see that the highlighted text is incorrect - it contains the text ' especi' and not the search term 'acute' - it is not a positioning issue.  (see screenshot).

I am using Chrome 39, windows 8.1 x64 and pdf.js 1.0.1093

![image](https://cloud.githubusercontent.com/assets/10129039/5864096/f2d665a4-a276-11e4-91fa-af6eb36f0cde.png)

if (this._extractTextPromises.length > 0) {
      return;
    }
    let promise = Promise.resolve();
    for (let i = 0, ii = this._linkService.pagesCount; i < ii; i++) {
      const extractTextCapability = createPromiseCapability();
      this._extractTextPromises[i] = extractTextCapability.promise;
      promise = promise.then(() => {
        return this._pdfDocument
          .getPage(i + 1)
          .then(pdfPage => {
            return pdfPage.getTextContent({
              normalizeWhitespace: true,
            });
          })
          .then(
            textContent => {
              const textItems = textContent.items;
              const strBuf = [];
              for (let j = 0, jj = textItems.length; j < jj; j++) {
                strBuf.push(textItems[j].str);
              }
              
              this._pageContents[i] = normalize(strBuf.join(""));
              extractTextCapability.resolve(i);
            },
            reason => {
              console.error(