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.
await loadingTask.destroy();
    });
    it("gets operator list", async function () {
      const operatorList = await page.getOperatorList();
      expect(operatorList.fnArray.length).toBeGreaterThan(100);
      expect(operatorList.argsArray.length).toBeGreaterThan(100);
      expect(operatorList.lastChunk).toEqual(true);
    });
    it("gets operatorList with JPEG image (issue 4888)", async function () {
      const loadingTask = getDocument(buildGetDocumentParams("cmykjpeg.pdf"));
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const operatorList = await pdfPage.getOperatorList();
      const imgIndex = operatorList.fnArray.indexOf(OPS.paintImageXObject);
      const imgArgs = operatorList.argsArray[imgIndex];
      const { data } = pdfPage.objs.get(imgArgs[0]);
      expect(data instanceof Uint8ClampedArray).toEqual(true);
      expect(data.length).toEqual(90000);
      await loadingTask.destroy();
    });
    it(
      "gets operatorList, from corrupt PDF file (issue 8702), " +
        "with/without `stopAtErrors` set",
      async function () {
        const loadingTask1 = getDocument(
          buildGetDocumentParams("issue8702.pdf", {
            stopAtErrors: false, 
          })
        );
        const loadingTask2 = getDocument(