layout: Don't build input region rects on Wayland

This is an X11-specific routine, and building the list of input region rects
on Wayland is a waste, since it incurs in many trampolines only to throw them
in the trash.

Don't build input region rects on Wayland. By modifying the 'wantsInputRegion'
variable, it also skips actors that only update input, which is another small
optimization for Wayland.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1678>

js/ui/layout.js

@@ -959,7 +959,10 @@ var LayoutManager = GObject.registerClass({
 
         let rects = [], struts = [], i;
         let isPopupMenuVisible = global.top_window_group.get_children().some(isPopupMetaWindow);
-        const wantsInputRegion = !isPopupMenuVisible && Main.modalCount === 0;
+        const wantsInputRegion =
+            !isPopupMenuVisible &&
+            Main.modalCount === 0 &&
+            !Meta.is_wayland_compositor();
 
         for (i = 0; i < this._trackedActors.length; i++) {
             let actorData = this._trackedActors[i];