Simplify annotations in runtime check tests.

pkg/front_end/testcases/runtime_checks/covariant_generic_parameter.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;
 
 class C<T> {
-  void f(T /*@checkFormal=semiSafe*/ x) {}
+  void f(T /*@checkFormal=semiSafe*/ /*@checkInterface=semiTyped*/ x) {}
 }
 
 void g1(C<num> c) {
-  c.f /*@checkCall=interface(semiTyped:0)*/ (1.5);
+  c.f(1.5);
 }
 
 void g2(C<int> c) {
-  c.f /*@checkCall=interface(semiTyped:0)*/ (1);
+  c.f(1);
 }
 
 void g3(C<num> c) {
-  c.f /*@checkCall=interface(semiTyped:0)*/ (null);
+  c.f(null);
 }
 
 main() {}