Ensure only whitelisted stubs have sse2 versions in the snapshot.

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 124 matching lines @@
 
 
 // Enable a unsupported feature within a scope for cross-compiling for a
 // different CPU.
 class PlatformFeatureScope BASE_EMBEDDED {
  public:
   explicit PlatformFeatureScope(CpuFeature f);
   ~PlatformFeatureScope();
 
  private:
-  uint64_t old_supported_;
-  uint64_t old_found_by_runtime_probing_only_;
+  uint64_t old_cross_compile_;
 };
 
 
 // -----------------------------------------------------------------------------
 // Labels represent pc locations; they are typically jump or call targets.
 // After declaration, a label can be freely used to denote known or (yet)
 // unknown pc location. Assembler::bind() is used to bind a label to the
 // current pc. A label can be bound only once.
 
 class Label BASE_EMBEDDED {
@@ skipping 912 matching lines @@
  public:
   NullCallWrapper() { }
   virtual ~NullCallWrapper() { }
   virtual void BeforeCall(int call_size) const { }
   virtual void AfterCall() const { }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ASSEMBLER_H_