Roll Dart SDK from d04e8b571819 to ab64c4a56e2c (1 revision) (#41798)

https://dart.googlesource.com/sdk.git/+log/d04e8b571819..ab64c4a56e2c

2023-05-06 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com Version 3.1.0-84.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC aam@google.com,dart-vm-team@google.com,jimgraham@google.com,rmistry@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter Engine: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -53,7 +53,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/main/DEPS
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'd04e8b57181980ada3106e50b620b8eeaea03df9',
+  'dart_revision': 'ab64c4a56e2cf350d69b15fbaabb37ebe29f536f',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py