Resynthesize positional/named parameters as DefaultParameterElementImpl.

pkg/analyzer/test/src/summary/resynthesize_test.dart

Index: pkg/analyzer/test/src/summary/resynthesize_test.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_test.dart b/pkg/analyzer/test/src/summary/resynthesize_test.dart
index 90b032f7b4072aabf0d0cae337c0fa93dc8bd4c2..702107052ea93ff18fd952ca4a44cd4a50942d53 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_test.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_test.dart
@@ -1582,7 +1582,9 @@ 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}) {}
 }
 ''');
   }