dependencies: Upgrade to WebRender 0.64 (#31486)

This brings the version of WebRender used in Servo up-to-date with Gecko
upstream. The big change here is that HiDPI is no longer handled via
WebRender. Instead this happens via a scale applied to the root layer in
the compositor. In addition to this change, various changes are made to
Servo to adapt to the new WebRender API.

Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>

components/script/dom/document.rs

@@ -1174,7 +1174,7 @@ impl Document {
                     kind,
                     text,
                     multiline,
-                    DeviceIntRect::from_untyped(&rect),
+                    DeviceIntRect::from_untyped(&rect.to_box2d()),
                 ));
             }
         }