Revert "[cleanup] Remove harmony-intl-dateformat-day-period"

This reverts commit 5e041b82.

Reason for revert: Mysterious breakage of SIMD tests: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Mac64/41767/overview

Original change's description:
> [cleanup] Remove harmony-intl-dateformat-day-period
>
> harmony-intl-dateformat-day-period is shipped in M92
>
> Bug: v8:12109
> Change-Id: I7d24463c0cc353c4baf52326159beb04592b81b5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3099087
> Reviewed-by: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Frank Tang <ftang@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#76468}

Bug: v8:12109
Change-Id: If7f32c650dc88bf6280573db9d6e42f89277778e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3116806
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#76470}

src/flags/flag-definitions.h

@@ -325,6 +325,8 @@ DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
 #ifdef V8_INTL_SUPPORT
 #define HARMONY_SHIPPING(V)                               \
   HARMONY_SHIPPING_BASE(V)                                \
+  V(harmony_intl_dateformat_day_period,                   \
+    "Add dayPeriod option to DateTimeFormat")             \
   V(harmony_intl_displaynames_v2, "Intl.DisplayNames v2") \
   V(harmony_intl_more_timezone,                           \
     "Extend Intl.DateTimeFormat timeZoneName Option")

src/init/bootstrapper.cc

@@ -4402,6 +4402,7 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_error_cause)
 #ifdef V8_INTL_SUPPORT
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_intl_best_fit_matcher)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_intl_displaynames_v2)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_intl_dateformat_day_period)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_intl_more_timezone)
 #endif  // V8_INTL_SUPPORT
 

src/objects/js-date-time-format.cc

@@ -144,14 +144,16 @@ static std::vector<PatternItem> BuildPatternItems() {
                               kNarrowLongShort2DigitNumeric));
   items.push_back(PatternItem("day", {{"dd", "2-digit"}, {"d", "numeric"}},
                               k2DigitNumeric));
-  items.push_back(PatternItem("dayPeriod",
-                              {{"BBBBB", "narrow"},
-                               {"bbbbb", "narrow"},
-                               {"BBBB", "long"},
-                               {"bbbb", "long"},
-                               {"B", "short"},
-                               {"b", "short"}},
-                              kNarrowLongShort));
+  if (FLAG_harmony_intl_dateformat_day_period) {
+    items.push_back(PatternItem("dayPeriod",
+                                {{"BBBBB", "narrow"},
+                                 {"bbbbb", "narrow"},
+                                 {"BBBB", "long"},
+                                 {"bbbb", "long"},
+                                 {"B", "short"},
+                                 {"b", "short"}},
+                                kNarrowLongShort));
+  }
   items.push_back(PatternItem("hour",
                               {{"HH", "2-digit"},
                                {"H", "numeric"},
@@ -921,7 +923,9 @@ MaybeHandle<JSObject> JSDateTimeFormat::ToDateTimeOptions(
     // a. For each of the property names "dayPeriod", "hour", "minute",
     // "second", "fractionalSecondDigits", do
     std::vector<Handle<String>> list;
-    list.push_back(factory->dayPeriod_string());
+    if (FLAG_harmony_intl_dateformat_day_period) {
+      list.push_back(factory->dayPeriod_string());
+    }
     list.push_back(factory->hour_string());
     list.push_back(factory->minute_string());
     list.push_back(factory->second_string());

test/test262/testcfg.py

@@ -44,6 +44,7 @@ from testrunner.outproc import test262
 
 # TODO(littledan): move the flag mapping into the status file
 FEATURE_FLAGS = {
+  'Intl.DateTimeFormat-dayPeriod': '--harmony-intl-dateformat-day-period',
   'Intl.Locale-info': '--harmony_intl_locale_info',
   'Intl.DateTimeFormat-extend-timezonename': '--harmony_intl_more_timezone',
   'Intl.DisplayNames-v2': '--harmony_intl_displaynames_v2',