[turbofan] Fix exit control flow in TryCatchBuilder.

src/compiler/control-builders.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "control-builders.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 142 matching lines @@
 }
 
 
 void BlockBuilder::EndBlock() {
   break_environment_->Merge(environment());
   set_environment(break_environment_);
 }
 
 
 void TryCatchBuilder::BeginTry() {
+  exit_environment_ = environment()->CopyAsUnreachable();
   catch_environment_ = environment()->CopyAsUnreachable();
   catch_environment_->Push(the_hole());
 }
 
 
 void TryCatchBuilder::Throw(Node* exception) {
   environment()->Push(exception);
   catch_environment_->Merge(environment());
   environment()->Pop();
   environment()->MarkAsUnreachable();
 }
 
 
 void TryCatchBuilder::EndTry() {
-  exit_environment_ = environment();
+  exit_environment_->Merge(environment());
   exception_node_ = catch_environment_->Pop();
   set_environment(catch_environment_);
 }
 
 
 void TryCatchBuilder::EndCatch() {
   exit_environment_->Merge(environment());
   set_environment(exit_environment_);
 }
 
@@ skipping 24 matching lines @@
 }
 
 
 void TryFinallyBuilder::EndFinally() {
   // Nothing to be done here.
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8