Preserve exception message in iterator finalization.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 619ed89a942807cd3d55f7c5bb450452ea5e2392..f153397931ca3bf03888b9c281a6c2e2af858377 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -1199,8 +1199,10 @@ void BytecodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
   VisitNewLocalCatchContext(stmt->variable());
   builder()->StoreAccumulatorInRegister(context);
 
-  // Clear message object as we enter the catch block.
-  builder()->CallRuntime(Runtime::kInterpreterClearPendingMessage, no_reg, 0);
+  // If requested, clear message object as we enter the catch block.
+  if (stmt->clear_pending_message()) {
+    builder()->CallRuntime(Runtime::kInterpreterClearPendingMessage, no_reg, 0);
+  }
 
   // Load the catch context into the accumulator.
   builder()->LoadAccumulatorWithRegister(context);