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.
const basicApiFileName = "basicapi.pdf";
  const basicApiFileLength = 105779; 
  const basicApiGetDocumentParams = buildGetDocumentParams(basicApiFileName);
  let CanvasFactory;
  beforeAll(function () {
    CanvasFactory = new DefaultCanvasFactory();
  });
  afterAll(function () {
    CanvasFactory = null;
  });
  function waitSome(callback) {
    const WAIT_TIMEOUT = 10;
    setTimeout(function () {
      callback();
    }, WAIT_TIMEOUT);
  }
  describe("getDocument", function () {
    it("creates pdf doc from URL-string", async function () {
      const urlStr = TEST_PDFS_PATH + basicApiFileName;
      const loadingTask = getDocument(urlStr);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const pdfDocument = await loadingTask.promise;
      expect(typeof urlStr).toEqual("string");
      expect(pdfDocument instanceof PDFDocumentProxy).toEqual(true);
      expect(pdfDocument.numPages).toEqual(3);
      await loadingTask.destroy();
    });
    it("creates pdf doc from URL-object", async function () {
      if (isNodeJS) {
        pending("window.location is not supported in Node.js.");