Roll src/third_party/dart ea9b0cd0f5..57c970d87a (5 commits)

57c970d87a [dart/vm] Fix inconsistencies in intermediate representation
034fce1e39 [dart:io] unbreak build
7f323feefe [dart:io] Fix iOS https leaks
1c469617c5 TypeParameter.declaredElement is guaranteed to be a TypeParameterElement
14d21859e7 Make assertConnection failures easier to debug

DEPS

@@ -31,7 +31,7 @@ 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': 'ea9b0cd0f50c1ad44be258a6f5de50237240d76c',
+  'dart_revision': '57c970d87ae5bb242b80681021061c37fa3c0d74',
 
   # 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: 7155e4009a8f420e7ad21c7352510607
+Signature: 9ae094368fcc98ad26b5bb2c8b0dbbc0
 
 UNUSED LICENSES: