Do not leak message object beyond try-catch.

src/ppc/full-codegen-ppc.cc

Index: src/ppc/full-codegen-ppc.cc
diff --git a/src/ppc/full-codegen-ppc.cc b/src/ppc/full-codegen-ppc.cc
index 75415e14f5b9b6e06a02d6b95042fac646e0913b..16cf3e348b5c7a7e19c9066a9c97400ee9e51ec0 100644
--- a/src/ppc/full-codegen-ppc.cc
+++ b/src/ppc/full-codegen-ppc.cc
@@ -5387,6 +5387,16 @@ void FullCodeGenerator::ExitFinallyBlock() {
 }
 
 
+void FullCodeGenerator::EnterCatchBlock() {
+  DCHECK(!result_register().is(r4));
+  ExternalReference pending_message_obj =
+      ExternalReference::address_of_pending_message_obj(isolate());
+  __ LoadRoot(r4, Heap::kTheHoleValueRootIndex);
+  __ mov(ip, Operand(pending_message_obj));
+  __ StoreP(r4, MemOperand(ip));
+}
+
+
 #undef __