The testcase is changed because it was actually incorrect. Easy to
verify because:
> _NET_CURRENT_DESKTOP
> …
> The index of the current desktop. This is always an integer between 0
> and _NET_NUMBER_OF_DESKTOPS - 1.
Fixes#3696.
Also updates the viewports.
Finally, fixes an issue with _NET_CURRENT_DESKTOP not being updated
after a workspace rename. Example:
- workspaces 1, 2, 3
- rename workspace 1 to 5
- All workspaces changed their index but _NET_CURRENT_DESKTOP was not
updated
c9efa6dffe