Fix bug and refactor optimized try-catch.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 31471)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -482,6 +482,7 @@
 
   // Change the definition after use lists have been computed.
   inline void BindTo(Definition* definition);
+  inline void BindToEnvironment(Definition* definition);
 
   Value* Copy() { return new Value(definition_); }
 
@@ -1794,6 +1795,13 @@
 }
 
 
+inline void Value::BindToEnvironment(Definition* def) {
+  RemoveFromUseList();
+  set_definition(def);
+  def->AddEnvUse(this);
+}
+
+
 class PhiInstr : public Definition {
  public:
   PhiInstr(JoinEntryInstr* block, intptr_t num_inputs)
@@ -4305,19 +4313,19 @@
       : offset_in_bytes_(offset_in_bytes), type_(type) {
     ASSERT(type.IsZoneHandle());  // May be null if field is not an instance.
     SetInputAt(kValuePos, value);
-    SetInputAt(kDestPos, dest);
+    SetInputAt(kObjectPos, dest);
   }
 
   enum {
     kValuePos = 0,
-    kDestPos = 1
+    kObjectPos = 1
   };
 
   DECLARE_INSTRUCTION(StoreVMField)
   virtual CompileType* ComputeInitialType() const;
 
   Value* value() const { return inputs_[kValuePos]; }
-  Value* dest() const { return inputs_[kDestPos]; }
+  Value* dest() const { return inputs_[kObjectPos]; }
   intptr_t offset_in_bytes() const { return offset_in_bytes_; }
   const AbstractType& type() const { return type_; }