[cleanup] Delete MacroAssembler::CopyBytes, it is dead code

src/mips64/macro-assembler-mips64.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_MIPS_MACRO_ASSEMBLER_MIPS_H_
 #define V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 
 #include "src/assembler.h"
 #include "src/globals.h"
 #include "src/mips64/assembler-mips64.h"
@@ skipping 1172 matching lines @@
   // -------------------------------------------------------------------------
   // Exception handling.
 
   // Push a new stack handler and link into stack handler chain.
   void PushStackHandler();
 
   // Unlink the stack handler on top of the stack from the stack handler chain.
   // Must preserve the result register.
   void PopStackHandler();
 
-  // Copies a number of bytes from src to dst. All registers are clobbered. On
-  // exit src and dst will point to the place just after where the last byte was
-  // read or written and length will be zero.
-  void CopyBytes(Register src,
-                 Register dst,
-                 Register length,
-                 Register scratch);
-
   // Initialize fields with filler values.  Fields starting at |current_address|
   // not including |end_address| are overwritten with the value in |filler|.  At
   // the end the loop, |current_address| takes the value of |end_address|.
   void InitializeFieldsWithFiller(Register current_address,
                                   Register end_address, Register filler);
 
   // -------------------------------------------------------------------------
   // Support functions.
 
   // Machine code version of Map::GetConstructor().
@@ skipping 841 matching lines @@
     dd(GetLabelFunction(index));
   }
 }
 
 #define ACCESS_MASM(masm) masm->
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_