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.
expect(
        worker1.port !== worker2.port &&
          worker1.port !== worker3.port &&
          worker2.port !== worker3.port
      ).toEqual(true);
      worker1.destroy();
      worker2.destroy();
      worker3.destroy();
    });
    it("gets current workerSrc", function () {
      if (isNodeJS) {
        pending("Worker is not supported in Node.js.");
      }
      const workerSrc = PDFWorker.workerSrc;
      expect(typeof workerSrc).toEqual("string");
      expect(workerSrc).toEqual(GlobalWorkerOptions.workerSrc);
    });
  });
  describe("PDFDocument", function () {
    let pdfLoadingTask, pdfDocument;
    beforeAll(async function () {
      pdfLoadingTask = getDocument(basicApiGetDocumentParams);
      pdfDocument = await pdfLoadingTask.promise;
    });
    afterAll(async function () {
      await pdfLoadingTask.destroy();
    });
    it("gets number of pages", function () {
      expect(pdfDocument.numPages).toEqual(3);
    });