Do not leak message object beyond try-catch.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 6e26e7670cfc357883b16fb55d0f6bf77b7f55db..9878deb43639b98551fa71f5bf205926bd4ffa4a 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -5295,6 +5295,8 @@ void FullCodeGenerator::EnterFinallyBlock() {
       ExternalReference::address_of_pending_message_obj(isolate());
   __ Load(rdx, pending_message_obj);
   __ Push(rdx);
+
+  ClearPendingMessage();
 }
 
 
@@ -5319,6 +5321,15 @@ void FullCodeGenerator::ExitFinallyBlock() {
 }
 
 
+void FullCodeGenerator::ClearPendingMessage() {
+  DCHECK(!result_register().is(rdx));
+  ExternalReference pending_message_obj =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  __ LoadRoot(rdx, Heap::kTheHoleValueRootIndex);
+  __ Store(pending_message_obj, rdx);
+}
+
+
 #undef __