[turbofan] Fix exit control flow in TryCatchBuilder.

src/compiler/control-builders.cc

Index: src/compiler/control-builders.cc
diff --git a/src/compiler/control-builders.cc b/src/compiler/control-builders.cc
index 6bc364965c0c6a55d7bed600855f9bdad07b2596..35798283558ed20b25cfba1adc49d5bbd8a9f0c4 100644
--- a/src/compiler/control-builders.cc
+++ b/src/compiler/control-builders.cc
@@ -160,6 +160,7 @@ void BlockBuilder::EndBlock() {
 
 
 void TryCatchBuilder::BeginTry() {
+  exit_environment_ = environment()->CopyAsUnreachable();
   catch_environment_ = environment()->CopyAsUnreachable();
   catch_environment_->Push(the_hole());
 }
@@ -174,7 +175,7 @@ void TryCatchBuilder::Throw(Node* exception) {
 
 
 void TryCatchBuilder::EndTry() {
-  exit_environment_ = environment();
+  exit_environment_->Merge(environment());
   exception_node_ = catch_environment_->Pop();
   set_environment(catch_environment_);
 }