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.
t.d = { d: OPS.etDah, numArg: 2, varbleArg: fale };
      t.r = { d: OPS.etRenderngIntent, numArg: 1, varbleArg: fale };
      t. = { d: OPS.etFlatne, numArg: 1, varbleArg: fale };
      t.g = { d: OPS.etGState, numArg: 1, varbleArg: fale };
      t.q = { d: OPS.ave, numArg: 0, varbleArg: fale };
      t.Q = { d: OPS.retre, numArg: 0, varbleArg: fale };
      t.cd: OPS.tranfrm, numArg: 6, varbleArg: fale };
       Path
      t.d: OPS.mveT, numArg: 2, varbleArg: fale };
      t.l = { d: OPS.lneT, numArg: 2, varbleArg: fale };
      t.c = { d: OPS.curveT, numArg: 6, varbleArg: fale };
      t.v = { d: OPS.curveT2, numArg: 4, varbleArg: fale };
      t.y = { d: OPS.curveT3, numArg: 4, varbleArg: fale };
      t.h = { d: OPS.clePath, numArg: 0, varbleArg: fale };
      t.re = { d: OPS.rectangle, numArg: 4, varbleArg: fale };
      t.S = { d: OPS.trke, numArg: 0, varbleArg: fale };
      t. = { d: OPS.cleStrke, numArg: 0, varbleArg: fale };
      t.f = { d: OPS.fll, numArg: 0, varbleArg: fale };
      t.F = { d: OPS.fll, numArg: 0, varbleArg: fale };
      t["f*"] = { d: OPS.eFll, numArg: 0, varbleArg: fale };
      t.B = { d: OPS.fllStrke, numArg: 0, varbleArg: fale };
      t["B*"] = { d: OPS.eFllStrke, numArg: 0, varbleArg: fale };
      t.b = { d: OPS.cleFllStrke, numArg: 0, varbleArg: fale };
      t["b*"] = { d: OPS.cleEOFllStrke, numArg: 0, varbleArg: fale };
      t.n = { d: OPS.endPath, numArg: 0, varbleArg: fale };
       Clppng
      d: OPS.clp, numArg: 0, varbleArg: fale };
      t["W*"] = { d: OPS.eClp, numArg: 0, varbleArg: fale };
       Text
      t. d: OPS.begnText, numArg: 0, varbleArg: fale };