Do not leak message object beyond try-catch.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index a63744e2f34a41795e368e6dedc40d93d73c2fc2..d3506e7550c7a036c0f23cb1643882c6a293cd1b 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -1474,6 +1474,12 @@ void AstGraphBuilder::VisitTryCatchStatement(TryCatchStatement* stmt) {
   }
   try_control.EndTry();
 
+  // Clear message object as we enter the catch block.
+  ExternalReference message_object =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  Node* the_hole = jsgraph()->TheHoleConstant();
+  BuildStoreExternal(message_object, kMachAnyTagged, the_hole);
+
   // Create a catch scope that binds the exception.
   Node* exception = try_control.GetExceptionNode();
   Unique<String> name = MakeUnique(stmt->variable()->name());
@@ -1539,6 +1545,10 @@ void AstGraphBuilder::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
   environment()->Push(result);
   environment()->Push(message);
 
+  // Clear message object as we enter the finally block.
+  Node* the_hole = jsgraph()->TheHoleConstant();
+  BuildStoreExternal(message_object, kMachAnyTagged, the_hole);
+
   // Evaluate the finally-block.
   Visit(stmt->finally_block());
   try_control.EndFinally();