Fix summarization of trailing `dynamic` type arguments.

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 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
@@ skipping 1330 matching lines @@
   }
 
   test_setter_external() {
     checkLibrary('external void set x(int value);');
   }
 
   test_setters() {
     checkLibrary('void set x(int value) {} set y(value) {}');
   }
 
-  test_type_arguments_explicit() {
+  test_type_arguments_explicit_dynamic_dynamic() {
+    checkLibrary('Map<dynamic, dynamic> m;');
+  }
+
+  test_type_arguments_explicit_dynamic_int() {
+    checkLibrary('Map<dynamic, int> m;');
+  }
+
+  test_type_arguments_explicit_String_dynamic() {
+    checkLibrary('Map<String, dynamic> m;');
+  }
+
+  test_type_arguments_explicit_String_int() {
     checkLibrary('Map<String, int> m;');
   }
 
   test_type_arguments_implicit() {
     checkLibrary('Map m;');
   }
 
   test_type_dynamic() {
     checkLibrary('dynamic d;');
   }
@@ skipping 266 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }