Attach (recommended) or Link to PDF file here:
https://bitcoin.org/bitcoin.pdf

Configuration:
- Web browser and its version: all
- Operating system and its version: all
- PDF.js version: tested with 2.9.11, but most likely all versions
- Is a browser extension: no

Steps to reproduce the problem:
1. Type "a purely" (single space between "a" and "purely") - doesn't find anything
2. Type "a  purely" (two spaces between "a" and "purely") - finds the phrase

Sometimes even 3 spaces are necessary.

What is the expected behavior? (add screenshot)
![Screenshot from 2021-04-08 13-00-03](https://user-images.githubusercontent.com/6362989/114008903-57639a00-986b-11eb-903a-92bbebbd922b.png)

What went wrong? (add screenshot)
![Screenshot from 2021-04-08 13-01-53](https://user-images.githubusercontent.com/6362989/114008810-44e96080-986b-11eb-8232-f58a62ed7899.png)

This affects many PDFs because justify alignment is common enough.
});
  });
  describe("PDFDataRangeTransport", function () {
    let dataPromise;
    beforeAll(function () {
      const fileName = "tracemonkey.pdf";
      dataPromise = DefaultFileReaderFactory.fetch({
        path: TEST_PDFS_PATH + fileName,
      });
    });
    afterAll(function () {
      dataPromise = null;
    });
    it("should fetch document info and page using ranges", async function () {
      const initialDataLength = 4000;
      let fetches = 0;
      const data = await dataPromise;
      const initialData = data.subarray(0, initialDataLength);
      const transport = new PDFDataRangeTransport(data.length, initialData);
      transport.requestDataRange = function (begin, end) {
        fetches++;
        waitSome(function () {
          transport.onDataProgress(4000);
          transport.onDataRange(begin, data.subarray(begin, end));
        });
      };
      const loadingTask = getDocument(transport);
      const pdfDocument = await loadingTask.promise;
      expect(pdfDocument.numPages).toEqual(14);
      const pdfPage = await pdfDocument.getPage(10);