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.
if (isNodeJS) {
          pending("Cannot simulate cross-origin requests in Node.js");
        }
        const params = buildGetDocumentParams(filename, options);
        const url = new URL(params.url);
        if (url.hostname === "localhost") {
          url.hostname = "127.0.0.1";
        } else if (params.url.hostname === "127.0.0.1") {
          url.hostname = "localhost";
        } else {
          pending("Can only run cross-origin test on localhost!");
        }
        params.url = url.href;
        loadingTask = getDocument(params);