Get rid of promotedType=none annotations

pkg/front_end/testcases/inference/null_coalescing_operator_2.dart

Index: pkg/front_end/testcases/inference/null_coalescing_operator_2.dart
diff --git a/pkg/front_end/testcases/inference/null_coalescing_operator_2.dart b/pkg/front_end/testcases/inference/null_coalescing_operator_2.dart
index 3900d5a0ff3b9616f02ea30032233007cc98dad9..5791d03191d2eca2d6ec781b2afe5cd1a4eff68e 100644
--- a/pkg/front_end/testcases/inference/null_coalescing_operator_2.dart
+++ b/pkg/front_end/testcases/inference/null_coalescing_operator_2.dart
@@ -7,5 +7,5 @@ library test;
 
 main() {
   List<int> x;
-  List<num> y = /*@promotedType=none*/ x ?? /*@typeArgs=num*/ [];
+  List<num> y = x ?? /*@typeArgs=num*/ [];
 }