[intl] cleanup FormatDate runtime

https://chromium-review.googlesource.com/c/v8/v8/+/1178763 added
DateTimeFormat.prototype.format to the C++ side of things, removing the
need for the runtime function, but the function wasn't removed.

Bug: v8:5751
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Ie73fefb5477dfb7f04a4f8852e086a92332c05fc
Reviewed-on: https://chromium-review.googlesource.com/1189502
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55421}

src/runtime/runtime-intl.cc

@@ -229,18 +229,6 @@ RUNTIME_FUNCTION(Runtime_CreateDateTimeFormat) {
   return *local_object;
 }
 
-RUNTIME_FUNCTION(Runtime_FormatDate) {
-  HandleScope scope(isolate);
-
-  DCHECK_EQ(2, args.length());
-
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, date_format_holder, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Object, date, 1);
-
-  RETURN_RESULT_OR_FAILURE(
-      isolate, DateFormat::DateTimeFormat(isolate, date_format_holder, date));
-}
-
 RUNTIME_FUNCTION(Runtime_CreateNumberFormat) {
   HandleScope scope(isolate);
 

src/runtime/runtime.h

@@ -215,7 +215,6 @@ namespace internal {
   F(DefineWEProperty, 3, 1)                  \
   F(FormatList, 2, 1)                        \
   F(FormatListToParts, 2, 1)                 \
-  F(FormatDate, 2, 1)                        \
   F(GetDefaultICULocale, 0, 1)               \
   F(GetNumberOption, 5, 1)                   \
   F(IntlUnwrapReceiver, 5, 1)                \