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.
this._textDivProperties = new WeakMap();
    this._renderingDone = false;
    this._canceled = false;
    this._capability = createPromiseCapability();
    this._renderTimer = null;
    this._bounds = [];
    
    this._capability.promise
      .finally(() => {
        if (!this._enhanceTextSelection) {
          
          this._textDivProperties = null;
        }
        if (this._layoutTextCtx) {
          
          
          this._layoutTextCtx.canvas.width = 0;
          this._layoutTextCtx.canvas.height = 0;
          this._layoutTextCtx = null;
        }
      })
      .catch(() => {
        
      });
  }
  /**
   * Promise for textLayer rendering task completion.
   * @type {Promise<void>}
   */
  get promise() {