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>

servo-tidy.toml

@@ -68,6 +68,10 @@ packages = [
     "phf_codegen",
     "phf_generator",
     "phf_shared",
+
+    # These can be removed once winit, font-kit, etc are upgraded
+    "core-graphics",
+    "core-text",
 ]
 # Files that are ignored for all tidy and lint checks.
 files = [