Roll Dart SDK from 396b5fb to 4ee57c0 (6 revisions) (#18567)

Author: skia-flutter-autoroll

DEPS

@@ -34,7 +34,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '396b5fb7a97daab488ed8efa3c2fb5ae9c74ff40',
+  'dart_revision': '4ee57c08e0a6cff1420c0fc56e17f8ab30d3db07',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py