Remove the unused LoadInitialArrayMap.

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 1216 matching lines @@
   // transitioned_kind from the native context if the map in register
   // map_in_out is the cached Array map in the native context of
   // expected_kind.
   void LoadTransitionedArrayMapConditional(
       ElementsKind expected_kind,
       ElementsKind transitioned_kind,
       Register map_in_out,
       Register scratch,
       Label* no_map_match);
 
-  // Load the initial map for new Arrays from a JSFunction.
-  void LoadInitialArrayMap(Register function_in,
-                           Register scratch,
-                           Register map_out,
-                           bool can_have_holes);
-
   // Load the global function with the given index.
   void LoadGlobalFunction(int index, Register function);
   void LoadArrayFunction(Register function);
 
   // Load the initial map from the global function. The registers
   // function and map can be the same.
   void LoadGlobalFunctionInitialMap(Register function, Register map);
 
   // ---------------------------------------------------------------------------
   // Runtime calls
@@ skipping 361 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_