[intl] Remove redundant type checking system

src/js/i18n.js

Index: src/js/i18n.js
diff --git a/src/js/i18n.js b/src/js/i18n.js
index 18d13db9a2c2f96e88f2c96305486ec7cb933cc9..4ee4733cb90bf3fe27b85536872db7ca076f51af 100644
--- a/src/js/i18n.js
+++ b/src/js/i18n.js
@@ -1747,6 +1747,11 @@ function FormatDateToParts(dateValue) {
   if (!IS_OBJECT(this)) {
     throw %make_type_error(kCalledOnNonObject, this);
   }
+  if (!%IsInitializedIntlObjectOfType(this, 'dateformat')) {
+    throw %make_type_error(kIncompatibleMethodReceiver,
+                          'Intl.DateTimeFormat.prototype.formatToParts',
+                          this);
+  }
   var dateMs;
   if (IS_UNDEFINED(dateValue)) {
     dateMs = %DateCurrentTime();