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

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index 230197db4f47775a6856dd1eb05b74c3ffdbbdc9..d4dca48a8bd94f825f148f35e98901e155030929 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -841,14 +841,6 @@ class MacroAssembler: public Assembler {
                        Register scratch1, Register scratch2,
                        Label* gc_required);
 
-  // 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|.