[interpreter] Clear pending message object on handler entry.

src/runtime/runtime-interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <iomanip>
 
 #include "src/arguments.h"
 #include "src/frames-inl.h"
@@ skipping 235 matching lines @@
   CONVERT_SMI_ARG_CHECKED(bytecode_offset, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, accumulator, 2);
   OFStream os(stdout);
 
   // Print all output registers and accumulator.
   PrintRegisters(os, false, bytecode_array, bytecode_offset, accumulator);
   os << std::flush;
   return isolate->heap()->undefined_value();
 }
 
+RUNTIME_FUNCTION(Runtime_InterpreterClearPendingMessage) {
+  SealHandleScope shs(isolate);
+  DCHECK_EQ(0, args.length());
+  isolate->clear_pending_message();
+  return isolate->heap()->undefined_value();
+}
+
 }  // namespace internal
 }  // namespace v8