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.
state,
  matchesPerPage,
  selectedMatch,
  pageMatches = null,
  pageMatchesLength = null,
}) {
  return new Promise(function (resolve) {
    const eventState = Object.assign(
      Object.create(null),
      {
        source: this,
        type: "",
        query: null,
        caseSensitive: false,
        entireWord: false,
        phraseSearch: true,
        findPrevious: false,
      },
      state
    );
    eventBus.dispatch("find", eventState);