This seems to happen more often now, but interestingly it only seems to happen on Linux. The last run was in https://github.com/mozilla/pdf.js/pull/13021#issuecomment-786012076. @calixteman Could you take a look at this to see if we can make the tests pass again?

The relevant log output is:

```
Failures:
1) Interaction in js-colors.pdf must changes colors
  Message:
[31m    In firefox: Expected 'rgba(0, 54, 255, 0.13)' to equal 'rgb(255, 0, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgba(0, 54, 255, 0.13)' to equal 'rgb(255, 0, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:661:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:667:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:676:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:661:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:667:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:676:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:661:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:667:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:676:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 0, 255)' to equal 'rgb(255, 0, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:661:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(255, 0, 0)' to equal 'rgb(0, 255, 0)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:667:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
  Message:
[31m    In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.[0m
  Stack:
    Error: In firefox: Expected 'rgb(0, 255, 0)' to equal 'rgb(0, 0, 255)'.
        at <Jasmine>
        at Promise.all.pages.map (/home/ubuntu/pdfjs/botio-files-pdfjs/private/e2b7f68c964756b/test/integration/scripting_spec.js:676:16)
        at process._tickCallback (internal/process/next_tick.js:68:7)
```
}, ref);
            }
            for (const [refOpen, refClose, pageNumOpen, pageNumClose] of [
              [18, 50, 2, 1],
              [21, 19, 3, 2],
              [47, 20, 1, 3],
            ]) {
              text = await actAndWaitForInput(
                page,
                `#\\3${Math.floor(refOpen / 10)} ${refOpen % 10}R`,
                async () => {
                  await page.evaluate(refElem => {
                    window.document
                      .getElementById(`${refElem}R`)
                      .scrollIntoView();
                  }, refOpen);
                },
                false
              );
              expect(text)
                .withContext(`In ${browserName}`)
                .toEqual(`PageOpen ${pageNumOpen}`);
              text = await page.$eval(
                `#\\3${Math.floor(refClose / 10)} ${refClose % 10}R`,
                el => el.value
              );
              expect(text)
                .withContext(`In ${browserName}`)
                .toEqual(`PageClose ${pageNumClose}`);
            }