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

pkg/compiler/lib/src/ssa/jump_handler.dart

 // Copyright (c) 2016, 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 '../common.dart';
-import '../elements/elements.dart';
+import '../elements/jumps.dart';
 import '../tree/tree.dart' as ast;
 
 import 'graph_builder.dart';
 import 'locals_handler.dart';
 import 'nodes.dart';
 
 /// A single break/continue instruction.
 class _JumpHandlerEntry {
   final HJump jumpInstruction;
   final LocalsHandler locals;
@@ skipping 214 matching lines @@
             targetIndexMap[continueTarget] = switchIndex;
             assert(builder.jumpTargets[continueTarget] == null);
             builder.jumpTargets[continueTarget] = this;
           }
         }
       }
       switchIndex++;
     }
   }
 }