test: disable a failing Firefox test

[OrKoN]

No description provided.

[OrKoN]

cc @whimboo

[whimboo]

@OrKoN do you have some more details? How often is this test failing? Is it permanent or intermittent? And it seems to be MacOS only?

The failure is actually caused by a timeout:
https://github.com/puppeteer/puppeteer/runs/6189321000?check_suite_focus=true

  1) Launcher specs
       Puppeteer
         Puppeteer.launch
           should have custom URL when launching browser:
     Error: Timeout of 25000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (/Users/runner/work/puppeteer/puppeteer/test/launcher.spec.ts)
      at listOnTimeout (internal/timers.js:554:17)
      at processTimers (internal/timers.js:497:7)

Maybe it's related to my fix on bug https://bugzilla.mozilla.org/show_bug.cgi?id=1759169 and that we face a shutdown hang of Firefox.

[whimboo]

Actually lets move further discussion to issue #8283.