Cherrypick Dart SDK to 5e8b31a5fa48 (#21054) (#21060)

Cherrypick Dart SDK to 5e8b31a5fa48

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': 'f3a9ca88b6645ec599c1493147bfaf9f79a0aca4',
+  'dart_revision': '5e8b31a5fa48ab8cd86beb76a7530dd99dc568b0',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

-Signature: c60f11773c21127073d84a0f8a8867b8
+Signature: abc81395f01d5e7a718dc8c5c3765546
 
 UNUSED LICENSES: