Remove CheckNotRegistersEqual regexp-masm function from all architectures.

src/x64/regexp-macro-assembler-x64.h

 // Copyright 2010 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 48 matching lines @@
                                int cp_offset,
                                Label* on_failure,
                                bool check_end_of_string);
   // A "greedy loop" is a loop that is both greedy and with a simple
   // body. It has a particularly simple implementation.
   virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
   virtual void CheckNotAtStart(Label* on_not_at_start);
   virtual void CheckNotBackReference(int start_reg, Label* on_no_match);
   virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
                                                Label* on_no_match);
-  virtual void CheckNotRegistersEqual(int reg1, int reg2, Label* on_not_equal);
   virtual void CheckNotCharacter(uint32_t c, Label* on_not_equal);
   virtual void CheckNotCharacterAfterAnd(uint32_t c,
                                          uint32_t mask,
                                          Label* on_not_equal);
   virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
                                               uc16 minus,
                                               uc16 mask,
                                               Label* on_not_equal);
   virtual void CheckCharacterInRange(uc16 from,
                                      uc16 to,
@@ skipping 207 matching lines @@
   Label exit_label_;
   Label check_preempt_label_;
   Label stack_overflow_label_;
 };
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_X64_REGEXP_MACRO_ASSEMBLER_X64_H_