[x64] Get rid of the stupid SmiConstantRegister.

src/objects.h

 // Copyright 2012 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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/builtins.h"
@@ skipping 1309 matching lines @@
   V(kUnexpectedStringFunction, "Unexpected String function")                  \
   V(kUnexpectedStringType, "Unexpected string type")                          \
   V(kUnexpectedStringWrapperInstanceSize,                                     \
     "Unexpected string wrapper instance size")                                \
   V(kUnexpectedTypeForRegExpDataFixedArrayExpected,                           \
     "Unexpected type for RegExp data, FixedArray expected")                   \
   V(kUnexpectedValue, "Unexpected value")                                     \
   V(kUnexpectedUnusedPropertiesOfStringWrapper,                               \
     "Unexpected unused properties of string wrapper")                         \
   V(kUnimplemented, "unimplemented")                                          \
-  V(kUninitializedKSmiConstantRegister, "Uninitialized kSmiConstantRegister") \
   V(kUnknown, "Unknown")                                                      \
   V(kUnsupportedConstCompoundAssignment,                                      \
     "Unsupported const compound assignment")                                  \
   V(kUnsupportedCountOperationWithConst,                                      \
     "Unsupported count operation with const")                                 \
   V(kUnsupportedDoubleImmediate, "Unsupported double immediate")              \
   V(kUnsupportedLetCompoundAssignment, "Unsupported let compound assignment") \
   V(kUnsupportedLookupSlotInDeclaration,                                      \
     "Unsupported lookup slot in declaration")                                 \
   V(kUnsupportedNonPrimitiveCompare, "Unsupported non-primitive compare")     \
@@ skipping 9919 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_