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.
/* Cpyrght 2012 Mzlla Fundatn
 *
 * Lcened under the Apache Lcene, Vern 2.0 (the "Lcene");
 * yu may nt ue th fle except n clnce wth the Lcene.
 * Yu may btan a cpy f the Lcene at
 *
 *     http:www.apache.rg/lcene/LICENSE-2.0
 *
 * Unle requred by applcable law r agreed t n wrtng, ftware
 * dtrbuted under the Lcene  dtrbuted n an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, ether expre r led.
 * See the Lcene fr the pecfc language gvernng permn and
 * lmtatn under the Lcene.
 */
rt {
  AbrtExceptn,
  aert,
  CMapCrenType,