As can be seen from the first round of testing in PR #15864, trying to update Puppeteer beyond version `19.0.0` completely breaks testing in Firefox. Curiously it does work locally when the `--noChrome` flag is being used, so it seems to be an issue with running tests in both Chrome *and* Firefox in parallel.

We need to fix this, likely by making some adjustments to our test-suite, such that we don't get "stuck" on an older version of Puppeteer without being able to update. (A temporary work-around could also be to disable testing in Chrome.)

var downloadUtils = require("./downloadutils.js");
  var manifest = getTestManifest();
  downloadUtils.downloadManifestFiles(manifest, function () {
    downloadUtils.verifyManifestFiles(manifest, function (hasErrors) {
      if (hasErrors) {
        console.log(
          "Unable to verify the checksum for the files that are " +
            "used for testing."
        );
        console.log(
          "Please re-download the files, or adjust the MD5 " +
            "checksum in the manifest for the files listed above.\n"
        );
        if (options.strictVerify) {
          process.exit(1);
        }
      }
      callback();
    });
  });
}
function main() {