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

src/code-factory.h

Index: src/code-factory.h
diff --git a/src/code-factory.h b/src/code-factory.h
index 3dea75147ac66b3a3f37b7b2b0d1ae3956cc1dee..deb125f224d9221b579dd4accc806d0bfa06f0a0 100644
--- a/src/code-factory.h
+++ b/src/code-factory.h
@@ -72,6 +72,7 @@ class CodeFactory final {
   static Callable StringToNumber(Isolate* isolate);
   static Callable ToString(Isolate* isolate);
   static Callable ToName(Isolate* isolate);
+  static Callable ToInteger(Isolate* isolate);
   static Callable ToLength(Isolate* isolate);
   static Callable ToObject(Isolate* isolate);
   static Callable NumberToString(Isolate* isolate);