[builtins] Refactor the remaining Date builtins.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 40d87b6dd83270cd9622957beca8e04576a1ab1f..510e6d3aef46ff963aeea15fe65263258b97402a 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -19333,6 +19333,16 @@ Object* JSDate::GetUTCField(FieldIndex index,
 }
 
 
+// static
+Handle<Object> JSDate::SetValue(Handle<JSDate> date, double v) {
+  Isolate* const isolate = date->GetIsolate();
+  Handle<Object> value = isolate->factory()->NewNumber(v);
+  bool value_is_nan = std::isnan(v);
+  date->SetValue(*value, value_is_nan);
+  return value;
+}
+
+
 void JSDate::SetValue(Object* value, bool is_value_nan) {
   set_value(value);
   if (is_value_nan) {