Remove unused StubType's, freeing 2 bits in Code objects.

src/code-stubs.h

 // Copyright 2012 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 913 matching lines @@
     int index = IndexBits::decode(bit_field_);
     int offset = index * kPointerSize;
     if (is_inobject()) return offset;
     return FixedArray::kHeaderSize + offset;
   }
 
   bool unboxed_double() {
     return UnboxedDoubleBits::decode(bit_field_);
   }
 
-  virtual Code::StubType GetStubType() { return Code::FIELD; }
+  virtual Code::StubType GetStubType() { return Code::FAST; }
 
  protected:
   LoadFieldStub() : HandlerStub() { }
 
   void Initialize(Code::Kind kind,
                   bool inobject,
                   int index,
                   Representation representation) {
     bool unboxed_double = FLAG_track_double_fields && representation.IsDouble();
     bit_field_ = KindBits::encode(kind)
@@ skipping 1569 matching lines @@
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_