[stubs] Remove dead string copying code

src/ppc/code-stubs-ppc.h

Index: src/ppc/code-stubs-ppc.h
diff --git a/src/ppc/code-stubs-ppc.h b/src/ppc/code-stubs-ppc.h
index d394171d896ac97012a8a5659b3a1e105b47b7a0..56ba0e545b8a9e713e720bfd8f33ed189f1272cf 100644
--- a/src/ppc/code-stubs-ppc.h
+++ b/src/ppc/code-stubs-ppc.h
@@ -16,15 +16,6 @@ void ArrayNativeCode(MacroAssembler* masm, Label* call_generic_code);
 
 class StringHelper : public AllStatic {
  public:
-  // Generate code for copying a large number of characters. This function
-  // is allowed to spend extra time setting up conditions to make copying
-  // faster. Copying of overlapping regions is not supported.
-  // Dest register ends at the position after the last character written.
-  static void GenerateCopyCharacters(MacroAssembler* masm, Register dest,
-                                     Register src, Register count,
-                                     Register scratch,
-                                     String::Encoding encoding);
-
   // Compares two flat one-byte strings and returns result in r0.
   static void GenerateCompareFlatOneByteStrings(MacroAssembler* masm,
                                                 Register left, Register right,