Media keys test shouldn't timeout

[Ara Pulido]

Right now, media keys test times out after some seconds.
This is not really needed, as the user can always close the window.

Remove the timeout and explain in the test window to close it when done.

[Brendan Donegan (brendan-donegan)]

Not sure this is *totally* trivial, but shouldn't be too hard and it should be fixed.

[Daniel Manrique (roadmr)]

It's very easy to fix, line 398 of scripts/key_test has:

    GObject.timeout_add_seconds(EXIT_TIMEOUT, reporter.quit)

If this is removed, the test will NOT exit after EXIT_TIMEOUT seconds.

Then, each Reporter subclass has a few calls to self.show_text with the text shown to the user. The instructions for the text-mode test already show how to exit it manually:

        self.show_text(_("You can also close me by pressing ESC or Ctrl+C."))

The GtkReporter class doesn't:

        self.show_text(_("Please press each key on your keyboard."))
        self.show_text(_("If a key is not present in your keyboard, "
                         "press the 'Skip' button below it to remove it "
                         "from the test."))

but it's trivial to add.

[Po-Hsu Lin (cypressyew)]

Same problem could apply to Super key, Volume, and Mute tests

[Po-Hsu Lin (cypressyew)]

I think we don't need the instructions for the gtk-mode to show how to exit it manually, as there will be an "Exit" button on it. (Which will return 1 when pressed.)