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.)

startServer();
  const startUrl = `http:${host}:${server.port}/test/resources/reftest-analyzer.html#web=/test/eq.log`;
  startBrowser("firefox", startUrl).then(function (browser) {
    browser.on("disconnected", function () {
      stopServer();
      process.exit(0);
    });
  });
}
function startRefTest(masterMode, showRefImages) {