[Intl] Only set HourCycle if needed

* Change the logic to reflect the spec change of
  https://github.com/tc39/proposal-intl-datetime-style/pull/37/
* Move enum value of kUndefined to 0 to make unset behavior the same as
  kUndefined.
* Change the expectation of existing tests
* Additional tests - https://github.com/tc39/test262/pull/2385

Bug: v8:9826
Change-Id: Ic437b5f6414aa641ae73766d8c5fd5b9d352a230
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1846722Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64255}

src/objects/intl-objects.h

@@ -240,14 +240,14 @@ class Intl {
       Handle<JSFunction> constructor, bool has_initialized_slot);
 
   // enum for "caseFirst" option: shared by Intl.Locale and Intl.Collator.
-  enum class CaseFirst { kUpper, kLower, kFalse, kUndefined };
+  enum class CaseFirst { kUndefined, kUpper, kLower, kFalse };
 
   // Shared function to read the "caseFirst" option.
   V8_WARN_UNUSED_RESULT static Maybe<CaseFirst> GetCaseFirst(
       Isolate* isolate, Handle<JSReceiver> options, const char* method);
 
   // enum for "hourCycle" option: shared by Intl.Locale and Intl.DateTimeFormat.
-  enum class HourCycle { kH11, kH12, kH23, kH24, kUndefined };
+  enum class HourCycle { kUndefined, kH11, kH12, kH23, kH24 };
 
   static HourCycle ToHourCycle(const std::string& str);
 

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

@@ -1546,12 +1546,16 @@ MaybeHandle<JSDateTimeFormat> JSDateTimeFormat::New(
       isolate->factory()->NewFastOrSlowJSObjectFromMap(map));
   DisallowHeapAllocation no_gc;
   date_time_format->set_flags(0);
-  date_time_format->set_hour_cycle(hc);
   if (date_style != DateTimeStyle::kUndefined) {
     date_time_format->set_date_style(date_style);
   }
   if (time_style != DateTimeStyle::kUndefined) {
     date_time_format->set_time_style(time_style);
+    date_time_format->set_hour_cycle(hc);
+  }
+  if ((date_style == DateTimeStyle::kUndefined) &&
+      (time_style == DateTimeStyle::kUndefined)) {
+    date_time_format->set_hour_cycle(hc);
   }
   date_time_format->set_icu_locale(*managed_locale);
   date_time_format->set_icu_simple_date_format(*managed_format);

test/intl/date-format/property-override-date-style.js

@@ -32,8 +32,6 @@ var expectedProperties = [
   'calendar',
   'numberingSystem',
   'timeZone',
-  'hourCycle',
-  'hour12',
   'dateStyle',
 ];