implement LabeledStatement and Break in kernel

pkg/compiler/lib/src/elements/modelx.dart

Index: pkg/compiler/lib/src/elements/modelx.dart
diff --git a/pkg/compiler/lib/src/elements/modelx.dart b/pkg/compiler/lib/src/elements/modelx.dart
index b47936705dbcfcc5c626bf94fc614aa0446c7506..c2d2e75ae8cc45f0d91cfc5d4ab4e79400a14816 100644
--- a/pkg/compiler/lib/src/elements/modelx.dart
+++ b/pkg/compiler/lib/src/elements/modelx.dart
@@ -3209,7 +3209,7 @@ class JumpTargetX implements JumpTarget {
   final ExecutableElement executableContext;
   final Node statement;
   final int nestingLevel;
-  Link<LabelDefinition> labels = const Link<LabelDefinition>();
+  List<LabelDefinition> labels = <LabelDefinition>[];
   bool isBreakTarget = false;
   bool isContinueTarget = false;
 
@@ -3223,7 +3223,7 @@ class JumpTargetX implements JumpTarget {
 
   LabelDefinition addLabel(Label label, String labelName) {
     LabelDefinition result = new LabelDefinitionX(label, labelName, this);
-    labels = labels.prepend(result);

[Siggi Cherem (dart-lang), 2016/12/17 00:43:16]

It seems the order after this change will be reversed. I'm guessing that doesn't
matter in this case, but just double checking?

[Harry Terkelsen, 2016/12/17 00:50:36]

The order doesn't matter because they are all labels on the same target.

+    labels.add(result);
     return result;
   }