GDM's GNOME Shell floods the Journal with XFIXES/cursor issues on Buster

On feature/buster, a few seconds after logging in:

amnesia@amnesia:~$ sudo journalctl | grep -c 'gnome-shell.*: Failed to create XFIXES cursor: Failed to get cursor image'
[sudo] password for amnesia: 
9398

I think we might have a cursor issue.

In case that matters, this is through virt-manager/libvirt.

Related issues

• Related to #12213
• Related to #12092 (closed)

Original created by @CyrilBrulebois on 16305 (Redmine)