move: Fix off-screen window scroll handling on some windows

Disable off-screen window scrolling on fullscreen and override-redirect windows, as it does not make sense to handle them and leads to showing invalid shadows, and fix handling of CSD shadows.

• Fullscreen & co: This is easily visible with e.g. a full-screen window playing in Firefox, but also in many other apps (also affects override-redirect windows from shwomouse and highlightcontent plugins);
• CSD: take any CSD window (e.g. Evince), and see that it draws scroll hint incorrectly on the right and bottom, and similarly scrolls the window too far up and left when it's shadow overflow the workarea (it should only scroll the window, not its shadow which doesn't matter and could lead to pushing the top/right too far).