PPC: [runtime] Add %ToString and %_ToString and remove the TO_STRING builtin.

src/ppc/macro-assembler-ppc.h

Index: src/ppc/macro-assembler-ppc.h
diff --git a/src/ppc/macro-assembler-ppc.h b/src/ppc/macro-assembler-ppc.h
index 26357ab2c79894093d5fa23aa537e0128711a5fe..1ea3e5cb153f46f81db6acceb0312ec26836ba02 100644
--- a/src/ppc/macro-assembler-ppc.h
+++ b/src/ppc/macro-assembler-ppc.h
@@ -887,21 +887,9 @@ class MacroAssembler : public Assembler {
 
   void BranchOnNoOverflow(Label* label) { bge(label, cr0); }
 
-  void RetOnOverflow(void) {
-    Label label;
+  void RetOnOverflow(void) { Ret(lt, cr0); }
 
-    blt(&label, cr0);
-    Ret();
-    bind(&label);
-  }
-
-  void RetOnNoOverflow(void) {
-    Label label;
-
-    bge(&label, cr0);
-    Ret();
-    bind(&label);
-  }
+  void RetOnNoOverflow(void) { Ret(ge, cr0); }
 
   // ---------------------------------------------------------------------------
   // Runtime calls