bug: https://bugzilla.mozilla.org/show_bug.cgi?id=739038
[delayed_window_print.html]
  comment: Our own save-to-pdf "printer" knows how to respect print.always_print_silent
  prefs: [print.always_print_silent:true, "print_printer:Mozilla Save to PDF"]
  disabled:
    if (asan or debug): https://bugzilla.mozilla.org/show_bug.cgi?id=1661162
