Resynthesize positional/named parameters as DefaultParameterElementImpl.

pkg/analyzer/test/src/summary/resynthesize_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 test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 1564 matching lines @@
 }
 ''');
   }
 
   test_const_parameterDefaultValue_normal() {
     checkLibrary(r'''
 class C {
   const C.positional([p = 1 + 2]);
   const C.named({p: 1 + 2});
   void methodPositional([p = 1 + 2]) {}
+  void methodPositionalWithoutDefault([p]) {}
   void methodNamed({p: 1 + 2}) {}
+  void methodNamedWithoutDefault({p}) {}
 }
 ''');
   }
 
   test_const_reference_staticField() {
     checkLibrary(r'''
 class C {
   static const int F = 42;
 }
 const V = C.F;
@@ skipping 1812 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }