Roll Dart SDK from 92315c4b2dc2 to 570a75be7ea5 (1 revision) (#20358)

diff --git a/DEPS b/DEPS
index 978e357..e063f53 100644
--- a/DEPS
+++ b/DEPS
@@ -34,7 +34,7 @@
   # 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': '92315c4b2dc24c13ce681a34992477991dafce48',
+  'dart_revision': '570a75be7ea5b1bcd91149599cd3c7523e9a9fd3',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py