Add `=` as default-value separator for named parameters.

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/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/error/error.dart';
@@ skipping 2752 matching lines @@
   }
 
   void test_withWithoutExtends() {
     createParser('class A with B, C {}');
     ClassDeclaration declaration =
         parser.parseClassDeclaration(emptyCommentAndMetadata(), null);
     expectNotNullIfNoErrors(declaration);
     listener.assertErrorsWithCodes([ParserErrorCode.WITH_WITHOUT_EXTENDS]);
   }
 
-  void test_wrongSeparatorForNamedParameter() {
-    createParser('(a, {b = 0})');
-    FormalParameterList list = parser.parseFormalParameterList();
-    expectNotNullIfNoErrors(list);
-    listener.assertErrorsWithCodes(
-        [ParserErrorCode.WRONG_SEPARATOR_FOR_NAMED_PARAMETER]);
-  }
-
   void test_wrongSeparatorForPositionalParameter() {
     createParser('(a, [b : 0])');
     FormalParameterList list = parser.parseFormalParameterList();
     expectNotNullIfNoErrors(list);
     listener.assertErrorsWithCodes(
         [ParserErrorCode.WRONG_SEPARATOR_FOR_POSITIONAL_PARAMETER]);
   }
 
   void test_wrongTerminatorForParameterGroup_named() {
     createParser('(a, {b, c])');
@@ skipping 10651 matching lines @@
   CompilationUnit _parseDirectives(String source,
       [List<ErrorCode> errorCodes = ErrorCode.EMPTY_LIST]) {
     createParser(source);
     CompilationUnit unit = parser.parseDirectives2();
     expect(unit, isNotNull);
     expect(unit.declarations, hasLength(0));
     listener.assertErrorsWithCodes(errorCodes);
     return unit;
   }
 }