Parameterize and move JumpTarget/LabelDefition to elements/jumps.dart

pkg/compiler/lib/src/kernel/element_map.dart

 // Copyright (c) 2017, 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.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../common/names.dart';
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../common_elements.dart';
-import '../elements/elements.dart' show JumpTarget;
 import '../elements/entities.dart';
+import '../elements/jumps.dart';
 import '../elements/names.dart';
 import '../elements/operators.dart';
 import '../elements/types.dart';
 import '../js_backend/backend.dart' show JavaScriptBackend;
 import '../native/native.dart' as native;
 import '../types/types.dart';
 import '../universe/call_structure.dart';
 import '../universe/selector.dart';
 import '../world.dart';
 import 'kernel_debug.dart';
@@ skipping 1010 matching lines @@
   Local getLocal(ir.VariableDeclaration node);
 
   /// Returns the [JumpTarget] for the branch in [node].
   // TODO(johnniwinther): Split this by kind of [node]?
   JumpTarget getJumpTarget(ir.TreeNode node, {bool isContinueTarget: false});
 
   /// Returns the [ClosureScope] for the loop [node] in [cloureData].
   ClosureScope getClosureScopeForLoop(
       ClosureClassMap closureData, ir.TreeNode node);
 }