[stubs] Introduce ToIntegerStub and unify the handling of %_ToInteger.

src/full-codegen/s390/full-codegen-s390.cc

Index: src/full-codegen/s390/full-codegen-s390.cc
diff --git a/src/full-codegen/s390/full-codegen-s390.cc b/src/full-codegen/s390/full-codegen-s390.cc
index 6aaee3e9142bc811d94549e7b165080ce867a4e3..2cfddd8423124ab6b09dba2b71e4b5cbbe376958 100644
--- a/src/full-codegen/s390/full-codegen-s390.cc
+++ b/src/full-codegen/s390/full-codegen-s390.cc
@@ -3040,22 +3040,6 @@ void FullCodeGenerator::EmitTwoByteSeqStringSetChar(CallRuntime* expr) {
   context()->Plug(string);
 }
 
-void FullCodeGenerator::EmitToInteger(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK_EQ(1, args->length());
-
-  // Load the argument into r2 and convert it.
-  VisitForAccumulatorValue(args->at(0));
-
-  // Convert the object to an integer.
-  Label done_convert;
-  __ JumpIfSmi(r2, &done_convert);
-  __ Push(r2);
-  __ CallRuntime(Runtime::kToInteger);
-  __ bind(&done_convert);
-  context()->Plug(r2);
-}
-
 void FullCodeGenerator::EmitStringCharFromCode(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);