Annotate targets of implicit this property gets/sets in inference tests.

pkg/front_end/testcases/inference/refine_binary_expression_type_type_parameter_t_t.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=inference*/
 library test;
 
 class C<T extends num> {
   T a;
 
   void op(T b) {
-    T r1 = a /*@target=num::+*/ + b;
-    T r2 = a /*@target=num::-*/ - b;
-    T r3 = a /*@target=num::**/ * b;
+    T r1 = /*@target=C::a*/ a /*@target=num::+*/ + b;
+    T r2 = /*@target=C::a*/ a /*@target=num::-*/ - b;
+    T r3 = /*@target=C::a*/ a /*@target=num::**/ * b;
   }
 
   void opEq(T b) {
-    a += b;
-    a -= b;
-    a *= b;
+    /*@target=C::a*/ a += b;
+    /*@target=C::a*/ a -= b;
+    /*@target=C::a*/ a *= b;
   }
 }
 
 main() {}