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.
.getAnnotations({ intent: "any" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const displayPromise = page
        .getAnnotations({ intent: "display" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const printPromise = page
        .getAnnotations({ intent: "print" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      await Promise.all([
        defaultPromise,
        anyPromise,
        displayPromise,
        printPromise,
      ]);
    });
    it("gets annotations containing relative URLs (bug 766086)", async function () {
      const filename = "bug766086.pdf";
      const defaultLoadingTask = getDocument(buildGetDocumentParams(filename));
      const defaultPromise = defaultLoadingTask.promise.then(function (pdfDoc) {
        return pdfDoc.getPage(1).then(function (pdfPage) {
          return pdfPage.getAnnotations();
        });
      });
      const docBaseUrlLoadingTask = getDocument(