Rollback Dart SDK to unblock the roller (#39722)

* Revert "Roll Dart SDK from c7ec16304216 to 8a7dc36cadf6 (1 revision) (#39716)"

This reverts commit 7e190a4.

* Revert "Roll Dart SDK from 42829b6f80b1 to c7ec16304216 (1 revision) (#39711)"

This reverts commit 4b0b8f0.

* Revert "Roll Dart SDK from 7642080abaf7 to 42829b6f80b1 (1 revision) (#39707)"

This reverts commit 1ae9473.

* Revert "Roll Dart SDK from 3ec7f1f92216 to 7642080abaf7 (2 revisions) (#39702)"

This reverts commit 6a2a46a.

Author: eyebrowsoffire

DEPS

@@ -48,7 +48,7 @@ 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': '8a7dc36cadf636115d2b33589e962cfe28455df8',
+  'dart_revision': '3ec7f1f922160727ba6e5b0989e3fea555eb5d82',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -386,7 +386,7 @@ deps = {
    Var('dart_git') + '/json_rpc_2.git@0280ac6cb4f3905d81c47ba927123ba2b95f7940',
 
   'src/third_party/dart/third_party/pkg/linter':
-   Var('dart_git') + '/linter.git@85d62c18e2a353abd4905aaf86e05dd1fc9d7b9a',
+   Var('dart_git') + '/linter.git@2a32d3f04394d02b80c53a460363b5ad4c413301',
 
   'src/third_party/dart/third_party/pkg/logging':
    Var('dart_git') + '/logging.git@abef3717d958158eb8b0ddb2871f4b15a9804cd4',

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 4f9a6052e1991179c5796eb45b7db3b9
+Signature: 5cf9493e2cab0d3aa50d13ccc411a98f
 
 ====================================================================================================
 LIBRARY: angle