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 pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const operatorList = await pdfPage.getOperatorList();
      expect(operatorList.fnArray.length).toBeGreaterThan(20);
      expect(operatorList.argsArray.length).toBeGreaterThan(20);
      expect(operatorList.lastChunk).toEqual(true);
      
      
      expect(operatorList.fnArray.includes(OPS.beginAnnotation)).toEqual(true);
      expect(operatorList.fnArray.includes(OPS.endAnnotation)).toEqual(true);
      await loadingTask.destroy();
    });
    it("gets operator list, with `annotationMode`-option", async function () {
      const loadingTask = getDocument(buildGetDocumentParams("evaljs.pdf"));
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(2);
      pdfDoc.annotationStorage.setValue("30R", { value: "test" });
      pdfDoc.annotationStorage.setValue("31R", { value: true });
      const opListAnnotDisable = await pdfPage.getOperatorList({
        annotationMode: AnnotationMode.DISABLE,
      });
      expect(opListAnnotDisable.fnArray.length).toEqual(0);
      expect(opListAnnotDisable.argsArray.length).toEqual(0);
      expect(opListAnnotDisable.lastChunk).toEqual(true);
      const opListAnnotEnable = await pdfPage.getOperatorList({
        annotationMode: AnnotationMode.ENABLE,
      });
      expect(opListAnnotEnable.fnArray.length).toBeGreaterThan(150);
      expect(opListAnnotEnable.argsArray.length).toBeGreaterThan(150);