Well. This is not Xorg-7.5 related - I just tested suspend-resume with Xvesa and although dmesg looks different, it also seems to crash the GPU. I don't know how I got a different result last time - with the transition to 3.x, I must have gotten confused about which kernel was involved.
So the bottom line is, suspend-resume no longer works with 18.104.22.168-tinycore. This stuff could be moved to its own kernel bug thread, I suppose?