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(typedArrayPdf.length).toEqual(basicApiFileLength);
      const loadingTask = getDocument(typedArrayPdf);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const progressReportedCapability = createPromiseCapability();
      loadingTask.onProgress = function (data) {
        progressReportedCapability.resolve(data);
      };
      const data = await Promise.all([
        loadingTask.promise,
        progressReportedCapability.promise,
      ]);
      expect(data[0] instanceof PDFDocumentProxy).toEqual(true);
      expect(data[1].loaded / data[1].total).toEqual(1);
      await loadingTask.destroy();
    });
    it("creates pdf doc from invalid PDF file", async function () {
      
      const loadingTask = getDocument(buildGetDocumentParams("bug1020226.pdf"));
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      try {
        await loadingTask.promise;
        
        expect(false).toEqual(true);
      } catch (reason) {
        expect(reason instanceof InvalidPDFException).toEqual(true);
        expect(reason.message).toEqual("Invalid PDF structure.");
      }
      await loadingTask.destroy();