Backout part of previous commit to fix bots

pkg/analyzer/test/generated/parser_test.dart

 // Copyright (c) 2014, 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.generated.parser_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_ast_factory.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 969 matching lines @@
     expect(unit, isNotNull);
   }
 
   void test_duplicatedModifier_const() {
     createParser('const const m;');
     ClassMember member = parser.parseClassMember('C');
     expectNotNullIfNoErrors(member);
     listener.assertErrorsWithCodes([ParserErrorCode.DUPLICATED_MODIFIER]);
   }
 
-  void test_duplicatedModifier_covariant() {
-    createParser('covariant covariant m;');
-    FormalParameter parameter =
-        parser.parseFormalParameter(ParameterKind.REQUIRED);
-    expectNotNullIfNoErrors(parameter);
-    listener.assertErrorsWithCodes([ParserErrorCode.DUPLICATED_MODIFIER]);
-  }
-
   void test_duplicatedModifier_external() {
     createParser('external external f();');
     ClassMember member = parser.parseClassMember('C');
     expectNotNullIfNoErrors(member);
     listener.assertErrorsWithCodes([ParserErrorCode.DUPLICATED_MODIFIER]);
   }
 
   void test_duplicatedModifier_factory() {
     createParser('factory factory C() {}');
     ClassMember member = parser.parseClassMember('C');
@@ skipping 13604 matching lines @@
   CompilationUnit _parseDirectives(String source,
       [List<ErrorCode> errorCodes = const <ErrorCode>[]]) {
     createParser(source);
     CompilationUnit unit = parser.parseDirectives2();
     expect(unit, isNotNull);
     expect(unit.declarations, hasLength(0));
     listener.assertErrorsWithCodes(errorCodes);
     return unit;
   }
 }