Fix a long-standing bug in the computation of the live environments for bailouts. When visiting a l…

frog/leg/ssa/nodes.dart

Index: frog/leg/ssa/nodes.dart
===================================================================
--- frog/leg/ssa/nodes.dart	(revision 5281)
+++ frog/leg/ssa/nodes.dart	(working copy)
@@ -398,7 +398,7 @@
   }
 }
 
-class HBasicBlock extends HInstructionList {
+class HBasicBlock extends HInstructionList implements Hashable {
   // The [id] must be such that any successor's id is greater than
   // this [id]. The exception are back-edges.
   int id;
@@ -432,6 +432,8 @@
         dominatedBlocks = <HBasicBlock>[],
         bailouts = <HBailoutTarget>[];
 
+  int hashCode() => id;
+
   bool isNew() => status == STATUS_NEW;
   bool isOpen() => status == STATUS_OPEN;
   bool isClosed() => status == STATUS_CLOSED;