Fix #28120, strong mode allows field overrides

pkg/analyzer/test/src/task/strong/inferred_type_test.dart

 // Copyright (c) 2015, 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.
 
 library analyzer.test.src.task.strong.inferred_type_test;
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 3267 matching lines @@
 
     // Recursive cases: these infer in declaration order.
     expect(fns[7].type.toString(), '() → dynamic');
     expect(fns[8].type.toString(), '() → dynamic');
     expect(fns[9].type.toString(), '() → Stream<int>');
   }
 
   test_inferParameterType_setter_fromField() async {
     var mainUnit = await checkFileElement('''
 class C extends D {
-  /*error:INVALID_FIELD_OVERRIDE*/set foo(x) {}
+  set foo(x) {}
 }
 class D {
   int foo;
 }
 ''');
     var f = mainUnit.getType('C').accessors[0];
     expect(f.type.toString(), '(int) → void');
   }
 
   test_inferParameterType_setter_fromSetter() async {
@@ skipping 399 matching lines @@
 ''');
   }
 
   test_inferTypeOnOverriddenFields2() async {
     await checkFileElement('''
 class A {
   int x = 2;
 }
 
 class B extends A {
-  /*error:INVALID_FIELD_OVERRIDE*/get x => 3;
+  get x => 3;
 }
 
 foo() {
   String y = /*error:INVALID_ASSIGNMENT*/new B().x;
   int z = new B().x;
 }
 ''');
   }
 
   test_inferTypeOnOverriddenFields4() async {
@@ skipping 119 matching lines @@
   }
 
   test_inferTypesOnGenericInstantiations_4() async {
     await checkFileElement('''
 class A<T> {
   T x;
 }
 
 class B<E> extends A<E> {
   E y;
-  /*error:INVALID_FIELD_OVERRIDE*/get x => y;
+  get x => y;
 }
 
 foo() {
   int y = /*error:INVALID_ASSIGNMENT*/new B<String>().x;
   String z = new B<String>().x;
 }
 ''');
   }
 
   test_inferTypesOnGenericInstantiations_5() async {
@@ skipping 1301 matching lines @@
     await super.test_unsafeBlockClosureInference_methodCall_implicitTypeParam();
   }
 
   @failingTest
   @override
   test_unsafeBlockClosureInference_methodCall_implicitTypeParam_comment() async {
     await super
         .test_unsafeBlockClosureInference_methodCall_implicitTypeParam_comment();
   }
 }