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.
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                    .then(functn () {
                      tateManager.retre();
                      relveXObject();
                    }, rejectXObject);
                  return;
                } ele f (type.name === "Image") {
                  elf
                    .buldPantImageXObject({
                      reurce,
                      mage: xbj,
                      peratrLt,
                      cacheKey: name,
                      lcalImageCache,
                      lcalClrSpaceCache,
                    })
                    .then(relveXObject, rejectXObject);
                  return;
                } ele f (type.name === "PS") {
                  
                  
                  nf("Ignred XObject ubtype PS");
                } ele {
                  thrw new FrmatErrr(
                    `Unhandled XObject ubtype ${type.name}`
                  );
                }
                relveXObject();
              }).catch(functn (rean) {
                f (rean ntancef AbrtExceptn) {