[stubs] replaced ToString MacroAssembler Stub with CodeStubAssembler builtin

src/s390/code-stubs-s390.cc

Index: src/s390/code-stubs-s390.cc
diff --git a/src/s390/code-stubs-s390.cc b/src/s390/code-stubs-s390.cc
index 111b317bd77e02cb4dfb5bbd1ee46e2359d6bebc..06ed699decedef87b65687905c3421c1e67763fa 100644
--- a/src/s390/code-stubs-s390.cc
+++ b/src/s390/code-stubs-s390.cc
@@ -2431,39 +2431,6 @@ void SubStringStub::Generate(MacroAssembler* masm) {
   generator.SkipSlow(masm, &runtime);
 }
 
-void ToStringStub::Generate(MacroAssembler* masm) {
-  // The ToString stub takes one argument in r2.
-  Label done;
-  Label is_number;
-  __ JumpIfSmi(r2, &is_number);
-
-  __ CompareObjectType(r2, r3, r3, FIRST_NONSTRING_TYPE);
-  // r2: receiver
-  // r3: receiver instance type
-  __ blt(&done);
-
-  Label not_heap_number;
-  __ CmpP(r3, Operand(HEAP_NUMBER_TYPE));
-  __ bne(&not_heap_number);
-  __ bind(&is_number);
-  NumberToStringStub stub(isolate());
-  __ TailCallStub(&stub);
-  __ bind(&not_heap_number);
-
-  Label not_oddball;
-  __ CmpP(r3, Operand(ODDBALL_TYPE));
-  __ bne(&not_oddball);
-  __ LoadP(r2, FieldMemOperand(r2, Oddball::kToStringOffset));
-  __ Ret();
-  __ bind(&not_oddball);
-
-  __ push(r2);  // Push argument.
-  __ TailCallRuntime(Runtime::kToString);
-
-  __ bind(&done);
-  __ Ret();
-}
-
 void StringHelper::GenerateFlatOneByteStringEquals(MacroAssembler* masm,
                                                    Register left,
                                                    Register right,