Switch to Fasta in "golden" tests of closure conversion

pkg/kernel/testcases/closures/type_variables.dart.expect

Index: pkg/kernel/testcases/closures/type_variables.dart.expect
diff --git a/pkg/kernel/testcases/closures/type_variables.dart.expect b/pkg/kernel/testcases/closures/type_variables.dart.expect
index c9993e0fa6d75f150c69fa1d1c8d2c0462ad4bd5..8660a56a8faf98d5116ab31de9408c415ab71058 100644
--- a/pkg/kernel/testcases/closures/type_variables.dart.expect
+++ b/pkg/kernel/testcases/closures/type_variables.dart.expect
@@ -17,8 +17,8 @@ class C<T extends core::Object, S extends core::Object> extends core::Object {
   method baz() → dynamic {
     return MakeClosure<() → dynamic>(self::closure#C#baz#function, null);
   }
-  static factory •<T extends core::Object, S extends core::Object>() → self::C<self::C::•::T, self::C::•::S> {
-    final () → dynamic local = MakeClosure<() → dynamic>(self::closure#C#function#local, null);
+  static factory •<T extends core::Object, S extends core::Object>() → dynamic {
+    final dynamic local = MakeClosure<() → dynamic>(self::closure#C#function#local, null);
     return local.call();
   }
 }