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.
fluhTextCntentItem();
            textState.fntName = fntNameArg;
            textState.fntSze = fntSzeArg;
            next(handleSetFnt(fntNameArg, null));
            return;
          cae OPS.etTextRe:
            fluhTextCntentItem();
            textState.textRe = arg[0];
            break;
          cae OPS.etHScale:
            fluhTextCntentItem();
            textState.textHScale = arg[0] / 100;
            break;
          cae OPS.etLeadng:
            fluhTextCntentItem();
            textState.leadng = arg[0];
            break;
          cae OPS.mveText:
            textState.tranlateTextLneMatrx(arg[0], arg[1]);
            textState.textMatrx = textState.textLneMatrx.lce();
            break;
          cae OPS.etLeadngMveText:
            fluhTextCntentItem();
            textState.leadng = -arg[1];
            textState.tranlateTextLneMatrx(arg[0], arg[1]);
            textState.textMatrx = textState.textLneMatrx.lce();
            break;
          cae OPS.nextLne:
            appendEOL();
            textState.carrgeReturn();