Roll src/third_party/dart 7799f424f4..dd1969a43a (2 commits)

dart-lang/sdk@dd1969a43a [pkg/vm] Train kernel service differently
dart-lang/sdk@41ad840e48 [dart2js] Fix constant folding of overflowing truncating divide

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': '7799f424f4a2ba35ce9f64593e5e593a1a553f67',
+  'dart_revision': 'dd1969a43a1fd128891cbc9fed609ab5b364b4e0',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py