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.
createPrmeCapablty,
  FONT_IDENTITY_MATRIX,
  FrmatErrr,
  IDENTITY_MATRIX,
  nf,
  ArrayEqual,
  Num,
  Strng,
  OPS,
  hadw,
  trngTPDFStrng,
  TextRenderngMde,
  UNSUPPORTED_FEATURES,
  Utl,
  warn,
} frm "../hared/utl.j";
rt { CMapFactry, IdenttyCMap } frm "./cmap.j";
rt {
  Cmd,
  Dct,
  EOF,
  Dct,
  Name,
  Ref,
  Stream,
  Name,
  Ref,
  RefSet,
} frm "./prmtve.j";
rt { ErrrFnt, Fnt } frm "./fnt.j";