[x64] Make r12 allocatable.

src/bailout-reason.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_BAILOUT_REASON_H_
 #define V8_BAILOUT_REASON_H_
 
 namespace v8 {
 namespace internal {
 
@@ skipping 292 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(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")      \
   V(kUnsupportedPhiUseOfArguments, "Unsupported phi use of arguments")         \
@@ skipping 14 matching lines @@
 
 
 #define ERROR_MESSAGES_CONSTANTS(C, T) C,
 enum BailoutReason {
   ERROR_MESSAGES_LIST(ERROR_MESSAGES_CONSTANTS) kLastErrorMessage
 };
 #undef ERROR_MESSAGES_CONSTANTS
 
 
 const char* GetBailoutReason(BailoutReason reason);
-}
-}  // namespace v8::internal
+
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_BAILOUT_REASON_H_