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.
pending("Worker is not supported in Node.js.");
      }
      const worker = new PDFWorker({ name: "test1" });
      const loadingTask = getDocument(
        buildGetDocumentParams(basicApiFileName, {
          worker,
        })
      );
      loadingTask.promise.then(function () {
        const docWorker = loadingTask._worker;
        expect(!!docWorker).toEqual(false);
        
        const messageHandlerPort = loadingTask._transport.messageHandler.comObj;
        expect(messageHandlerPort === worker.port).toEqual(true);
      });
      const destroyPromise = loadingTask.promise.then(function () {
        return loadingTask.destroy();
      });
      await destroyPromise;
      expect(worker.destroyed).toEqual(false);
      worker.destroy();
    });
    it("creates more than one worker", async function () {
      if (isNodeJS) {
        pending("Worker is not supported in Node.js.");
      }
      const worker1 = new PDFWorker({ name: "test1" });
      const worker2 = new PDFWorker({ name: "test2" });
      const worker3 = new PDFWorker({ name: "test3" });
      await Promise.all([worker1.promise, worker2.promise, worker3.promise]);