Fix infer_instance_accessor_ref test

pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart

Index: pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart
diff --git a/pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart b/pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart
index d7b652f5bddf77b2e65078fc96ecd52e9c12cd3b..9abb41590d8d066de79599c64bf9c7920f9dbc40 100644
--- a/pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart
+++ b/pkg/front_end/testcases/inference_new/infer_instance_accessor_ref.dart
@@ -11,7 +11,7 @@ class A {
 
 class B {
   C get c => null;
-  void set(C value) {}
+  void set c(C value) {}
 }
 
 class C {}
@@ -20,6 +20,6 @@ class D extends C {}
 
 var /*@topType=A*/ a = new A();
 var /*@topType=C*/ x = a. /*@target=A::b*/ b. /*@target=B::c*/ c;
-var /*@topType=dynamic*/ y = a. /*@target=A::b*/ b.c ??= new D();
+var /*@topType=C*/ y = a. /*@target=A::b*/ b. /*@target=B::c*/ c ??= new D();
 
 main() {}