[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/builtins/ppc/builtins-ppc.cc

Index: src/builtins/ppc/builtins-ppc.cc
diff --git a/src/builtins/ppc/builtins-ppc.cc b/src/builtins/ppc/builtins-ppc.cc
index 36bfc4b97f5069d7a6e92c49db0edfabcf87186c..62390158ca0402d54263799d3a871e3abcae2bab 100644
--- a/src/builtins/ppc/builtins-ppc.cc
+++ b/src/builtins/ppc/builtins-ppc.cc
@@ -398,10 +398,9 @@ void Builtins::Generate_StringConstructor(MacroAssembler* masm) {
   __ bind(&to_string);
   {
     FrameScope scope(masm, StackFrame::MANUAL);
-    ToStringStub stub(masm->isolate());
     __ SmiTag(r5);
     __ EnterBuiltinFrame(cp, r4, r5);
-    __ CallStub(&stub);
+    __ Call(masm->isolate()->builtins()->ToString(), RelocInfo::CODE_TARGET);
     __ LeaveBuiltinFrame(cp, r4, r5);
     __ SmiUntag(r5);
   }
@@ -462,12 +461,11 @@ void Builtins::Generate_StringConstructor_ConstructStub(MacroAssembler* masm) {
     __ bind(&convert);
     {
       FrameScope scope(masm, StackFrame::MANUAL);
-      ToStringStub stub(masm->isolate());
       __ SmiTag(r9);
       __ EnterBuiltinFrame(cp, r4, r9);
       __ Push(r6);
       __ mr(r3, r5);
-      __ CallStub(&stub);
+      __ Call(masm->isolate()->builtins()->ToString(), RelocInfo::CODE_TARGET);
       __ mr(r5, r3);
       __ Pop(r6);
       __ LeaveBuiltinFrame(cp, r4, r9);