fix missing CJK and symbol glyphs, font precedence, fallback reset (flutter#24470)

* fix missing CJK and symbol glyphs
* Cache known covered code units

Co-authored-by: Harry Terkelsen <[email protected]>

Author: yjbanov

lib/web_ui/dev/goldens_lock.yaml

@@ -1,2 +1,2 @@
 repository: https://github.com/flutter/goldens.git
-revision: 2eb81061582dbe73939811d4471d6167b463f11c
+revision: ec80c8042759905a5215ab1cd87ad280e8ef3cd7

lib/web_ui/lib/src/engine/canvaskit/canvaskit_api.dart

@@ -1643,6 +1643,8 @@ class SkTypeface {}
 class SkFont {
   external SkFont(SkTypeface typeface);
   external Uint8List getGlyphIDs(String text);
+  external void getGlyphBounds(
+      List<int> glyphs, SkPaint? paint, Uint8List? output);
 }
 
 @JS()