Remove (untested) code for unsupported compilers.

src/base/compiler-specific.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_BASE_COMPILER_SPECIFIC_H_
 #define V8_BASE_COMPILER_SPECIFIC_H_
 
 #include "include/v8config.h"
 
 // Annotate a typedef or function indicating it's ok if it's not used.
@@ skipping 19 matching lines @@
 
 // Annotate a virtual method indicating that subclasses must not override it,
 // or annotate a class to indicate that it cannot be subclassed.
 // Use like:
 //   class B FINAL : public A {};
 //   virtual void bar() FINAL;
 #if V8_HAS_CXX11_FINAL
 #define FINAL final
 #elif V8_HAS___FINAL
 #define FINAL __final
-#elif V8_HAS_SEALED
-#define FINAL sealed
 #else
 #define FINAL /* NOT SUPPORTED */
 #endif
 
 
 // Annotate a function indicating the caller must examine the return value.
 // Use like:
 //   int foo() WARN_UNUSED_RESULT;
 #if V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 #else
 #define WARN_UNUSED_RESULT /* NOT SUPPORTED */
 #endif
 
 #endif  // V8_BASE_COMPILER_SPECIFIC_H_