Simplify annotations in runtime check tests.

pkg/front_end/testcases/runtime_checks/covariant_setter.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /*@testedFeatures=checks*/
 library test;
 
 typedef void F<T>(T x);
 
 class C<T> {
-  T /*@checkFormal=semiSafe*/ x;
-  void f(T /*@checkFormal=semiSafe*/ value) {
+  T /*@checkFormal=semiSafe*/ /*@checkInterface=semiTyped*/ x;
+  void f(T /*@checkFormal=semiSafe*/ /*@checkInterface=semiTyped*/ value) {
     this.x = value;
   }
 }
 
 void g(C<num> c) {
-  c. /*@checkCall=interface(semiTyped:0)*/ x = 1.5;
+  c.x = 1.5;
 }
 
 void main() {}