Remove unused SmiTryAddConstant from X64 macro assembler

src/x64/macro-assembler-x64.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 514 matching lines @@
   // Jump if either or both register are not non-negative smi values.
   void JumpUnlessBothNonNegativeSmi(Register src1, Register src2,
                                     Label* on_not_both_smi,
                                     Label::Distance near_jump = Label::kFar);
 
   // Operations on tagged smi values.
 
   // Smis represent a subset of integers. The subset is always equivalent to
   // a two's complement interpretation of a fixed number of bits.
 
-  // Optimistically adds an integer constant to a supposed smi.
-  // If the src is not a smi, or the result is not a smi, jump to
-  // the label.
-  void SmiTryAddConstant(Register dst,
-                         Register src,
-                         Smi* constant,
-                         Label* on_not_smi_result,
-                         Label::Distance near_jump = Label::kFar);
-
   // Add an integer constant to a tagged smi, giving a tagged smi as result.
   // No overflow testing on the result is done.
   void SmiAddConstant(Register dst, Register src, Smi* constant);
 
   // Add an integer constant to a tagged smi, giving a tagged smi as result.
   // No overflow testing on the result is done.
   void SmiAddConstant(const Operand& dst, Smi* constant);
 
   // Add an integer constant to a tagged smi, giving a tagged smi as result,
   // or jumping to a label if the result cannot be represented by a smi.
@@ skipping 1027 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_