[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/builtins/mips/builtins-mips.cc

Index: src/builtins/mips/builtins-mips.cc
diff --git a/src/builtins/mips/builtins-mips.cc b/src/builtins/mips/builtins-mips.cc
index 5a37e2d5c15ec43649e43bdfb86739abb9ccdfc1..a2b6bea626a1323371e0b94efd308b16c22e46ed 100644
--- a/src/builtins/mips/builtins-mips.cc
+++ b/src/builtins/mips/builtins-mips.cc
@@ -395,10 +395,9 @@ void Builtins::Generate_StringConstructor(MacroAssembler* masm) {
   __ bind(&to_string);
   {
     FrameScope scope(masm, StackFrame::MANUAL);
-    ToStringStub stub(masm->isolate());
     __ SmiTag(t0);
     __ EnterBuiltinFrame(cp, a1, t0);
-    __ CallStub(&stub);
+    __ Call(masm->isolate()->builtins()->ToString(), RelocInfo::CODE_TARGET);
     __ LeaveBuiltinFrame(cp, a1, t0);
     __ SmiUntag(t0);
   }
@@ -459,11 +458,10 @@ void Builtins::Generate_StringConstructor_ConstructStub(MacroAssembler* masm) {
     __ bind(&convert);
     {
       FrameScope scope(masm, StackFrame::MANUAL);
-      ToStringStub stub(masm->isolate());
       __ SmiTag(t0);
       __ EnterBuiltinFrame(cp, a1, t0);
       __ Push(a3);
-      __ CallStub(&stub);
+      __ Call(masm->isolate()->builtins()->ToString(), RelocInfo::CODE_TARGET);
       __ Move(a0, v0);
       __ Pop(a3);
       __ LeaveBuiltinFrame(cp, a1, t0);