Fix 'Unused local variable' hints in analyzer and analysis_server.

pkg/analysis_server/test/services/search/hierarchy_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 test.services.src.search.hierarchy;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_memory_index.dart';
@@ skipping 82 matching lines @@
   set foo(x) {}
 }
 class D {
   int foo;
 }
 ''');
     ClassElement classA = findElement("A");
     ClassElement classB = findElement("B");
     ClassElement classC = findElement("C");
     ClassElement classD = findElement("D");
-    ClassElement classE = findElement("E");
     ClassMemberElement memberA = classA.fields[0];
     ClassMemberElement memberB = classB.fields[0];
     ClassMemberElement memberC = classC.fields[0];
     ClassMemberElement memberD = classD.fields[0];
     var futureA = getHierarchyMembers(searchEngine, memberA).then((members) {
       expect(members, unorderedEquals([memberA, memberB, memberC]));
     });
     var futureB = getHierarchyMembers(searchEngine, memberB).then((members) {
       expect(members, unorderedEquals([memberA, memberB, memberC]));
     });
@@ skipping 64 matching lines @@
 }
 class D extends C {
   foo() {}
 }
 class E {
   foo() {}
 }
 ''');
     ClassElement classA = findElement("A");
     ClassElement classB = findElement("B");
-    ClassElement classC = findElement("C");
     ClassElement classD = findElement("D");
-    ClassElement classE = findElement("E");
     ClassMemberElement memberA = classA.methods[0];
     ClassMemberElement memberB = classB.methods[0];
     ClassMemberElement memberD = classD.methods[0];
     var futureA = getHierarchyMembers(searchEngine, memberA).then((members) {
       expect(members, unorderedEquals([memberA, memberB, memberD]));
     });
     var futureB = getHierarchyMembers(searchEngine, memberB).then((members) {
       expect(members, unorderedEquals([memberA, memberB, memberD]));
     });
     var futureD = getHierarchyMembers(searchEngine, memberD).then((members) {
@@ skipping 112 matching lines @@
       Set<ClassElement> supers = getSuperClasses(classF);
       expect(supers, unorderedEquals([objectElement, classA]));
     }
   }
 
   void _indexTestUnit(String code) {
     resolveTestUnit(code);
     index.indexUnit(context, testUnit);
   }
 }