[iwyu] Include handles.h less.

src/execution.h

 // Copyright 2014 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.
 
 #ifndef V8_EXECUTION_H_
 #define V8_EXECUTION_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
-#include "src/handles.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
+template <typename T>
+class Handle;
+
 class Execution final : public AllStatic {
  public:
   // Whether to report pending messages, or keep them pending on the isolate.
   enum class MessageHandling { kReport, kKeepPending };
 
   // Call a function, the caller supplies a receiver and an array
   // of arguments.
   //
   // When the function called is not in strict mode, receiver is
   // converted to an object.
@@ skipping 196 matching lines @@
   friend class StackLimitCheck;
   friend class PostponeInterruptsScope;
 
   DISALLOW_COPY_AND_ASSIGN(StackGuard);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_EXECUTION_H_