There used to be an arrow in the bottom right which would scroll back to the top.
I don’t recall having any options like smilies, text formatting, insert link, etc. These appear now on the quick reply option, but not on the post new reply or new post option.
For what it’s worth, the scroll-to-top arrow has disappeared for me, too, both on my desktop and in mobile. I know I’m in the minority, but I would prefer to have it back.
The scroll-up arrow which I did use sometimes is gone in FireFox as well. But on the good side so are the pop-under ads so all in all I’m calling it a win.
I don’t think taking out the button was intentional. It still seems to try and load the site that it comes from. My guess is that the change to HTTPS killed it, since it always mentions something about the TLS handshake (which is the S part of HTTPS).