Roll Dart SDK from 654db247514f to 3aa21e5c9ccd (1 revision) (flutter#34612)

https://dart.googlesource.com/sdk.git/+log/654db247514f..3aa21e5c9ccd

2022-07-11 dart-internal-sdk-dev-roller@dart-ci-internal.iam.gserviceaccount.com Version 2.18.0-272.0.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 [email protected],[email protected],[email protected] 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

@@ -35,7 +35,7 @@ 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': '654db247514fd82fe4037af9c7ef419cab8484b5',
+  'dart_revision': '3aa21e5c9ccdf677675ccd4cd44eb38242b8435b',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py