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 (!this._enhanceTextSelection || !this._renderingDone) {
      return;
    }
    if (this._bounds !== null) {
      expand(this);
      this._bounds = null;
    }
    const transformBuf = [],
      paddingBuf = [];
    for (let i = 0, ii = this._textDivs.length; i < ii; i++) {
      const div = this._textDivs[i];
      const divProps = this._textDivProperties.get(div);
      if (!divProps.hasText) {
        continue;
      }