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.
buildGetDocumentParams("annotation-line.pdf")
      );
      const pdfDoc = await loadingTask.promise;
      const markInfo = await pdfDoc.getMarkInfo();
      expect(markInfo.Marked).toEqual(true);
      expect(markInfo.UserProperties).toEqual(false);
      expect(markInfo.Suspects).toEqual(false);
    });
    it("gets data", async function () {
      const data = await pdfDocument.getData();
      expect(data instanceof Uint8Array).toEqual(true);
      expect(data.length).toEqual(basicApiFileLength);
    });
    it("gets download info", async function () {
      const downloadInfo = await pdfDocument.getDownloadInfo();
      expect(downloadInfo).toEqual({ length: basicApiFileLength });
    });
    it("gets document stats", async function () {
      const stats = await pdfDocument.getStats();
      expect(stats).toEqual({ streamTypes: {}, fontTypes: {} });
    });
    it("cleans up document resources", async function () {
      await pdfDocument.cleanup();
      expect(true).toEqual(true);
    });
    it("checks that fingerprints are unique", async function () {
      const loadingTask1 = getDocument(
        buildGetDocumentParams("issue4436r.pdf")
      );
      const loadingTask2 = getDocument(buildGetDocumentParams("issue4575.pdf"));