Probably don't need an unused re-implementation of addAll(). :)

pkg/analyzer/test/generated/utilities_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.utilities_test;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
@@ skipping 12 matching lines @@
 import 'test_support.dart';
 
 main() {
   initializeTestEnvironment();
   runReflectiveTests(AstClonerTest);
   runReflectiveTests(NodeReplacerTest);
   runReflectiveTests(LineInfoTest);
   runReflectiveTests(SourceRangeTest);
   runReflectiveTests(BooleanArrayTest);
   runReflectiveTests(DirectedGraphTest);
-  runReflectiveTests(ListUtilitiesTest);
   runReflectiveTests(MultipleMapIteratorTest);
   runReflectiveTests(SingleMapIteratorTest);
   runReflectiveTests(TokenMapTest);
   runReflectiveTests(StringUtilitiesTest);
 }
 
 class AstCloneComparator extends AstComparator {
   final bool expectTokensCopied;
 
   AstCloneComparator(this.expectTokensCopied);
@@ skipping 2705 matching lines @@
 
 class ListGetter_NodeReplacerTest_testSwitchMember_2
     extends NodeReplacerTest_ListGetter<SwitchMember, Statement> {
   ListGetter_NodeReplacerTest_testSwitchMember_2(int arg0) : super(arg0);
 
   @override
   NodeList<Statement> getList(SwitchMember node) => node.statements;
 }
 
 @reflectiveTest
-class ListUtilitiesTest {
-  void test_addAll_emptyToEmpty() {
-    List<String> list = new List<String>();
-    List<String> elements = <String>[];
-    ListUtilities.addAll(list, elements);
-    expect(list.length, 0);
-  }
-
-  void test_addAll_emptyToNonEmpty() {
-    List<String> list = new List<String>();
-    list.add("a");
-    List<String> elements = <String>[];
-    ListUtilities.addAll(list, elements);
-    expect(list.length, 1);
-  }
-
-  void test_addAll_nonEmptyToEmpty() {
-    List<String> list = new List<String>();
-    List<String> elements = ["b", "c"];
-    ListUtilities.addAll(list, elements);
-    expect(list.length, 2);
-  }
-
-  void test_addAll_nonEmptyToNonEmpty() {
-    List<String> list = new List<String>();
-    list.add("a");
-    List<String> elements = ["b", "c"];
-    ListUtilities.addAll(list, elements);
-    expect(list.length, 3);
-  }
-}
-
-@reflectiveTest
 class MultipleMapIteratorTest extends EngineTestCase {
   void test_multipleMaps_firstEmpty() {
     Map<String, String> map1 = new HashMap<String, String>();
     Map<String, String> map2 = new HashMap<String, String>();
     map2["k2"] = "v2";
     Map<String, String> map3 = new HashMap<String, String>();
     map3["k3"] = "v3";
     MultipleMapIterator<String, String> iterator =
         _iterator([map1, map2, map3]);
     expect(iterator.moveNext(), isTrue);
@@ skipping 1529 matching lines @@
   }
 
   void test_get_added() {
     TokenMap tokenMap = new TokenMap();
     Token key = TokenFactory.tokenFromType(TokenType.AT);
     Token value = TokenFactory.tokenFromType(TokenType.AT);
     tokenMap.put(key, value);
     expect(tokenMap.get(key), same(value));
   }
 }