LibJS: Remove Temporal::DefaultTimeZone

This is an editorial change in the Temporal spec. See:
https://github.com/tc39/proposal-temporal/commit/e232580

Userland/Libraries/LibJS/Runtime/Intl/DateTimeFormatConstructor.cpp

@@ -6,6 +6,7 @@
 
 #include <LibJS/Runtime/AbstractOperations.h>
 #include <LibJS/Runtime/Array.h>
+#include <LibJS/Runtime/Date.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/AbstractOperations.h>
 #include <LibJS/Runtime/Intl/DateTimeFormat.h>
@@ -216,7 +217,7 @@ ThrowCompletionOr<DateTimeFormat*> initialize_date_time_format(VM& vm, DateTimeF
     // 30. If timeZone is undefined, then
     if (time_zone_value.is_undefined()) {
         // a. Set timeZone to ! DefaultTimeZone().
-        time_zone = Temporal::default_time_zone();
+        time_zone = default_time_zone();
     }
     // 31. Else,
     else {

Userland/Libraries/LibJS/Runtime/Temporal/Now.cpp

@@ -7,6 +7,7 @@
 #include <AK/Time.h>
 #include <LibCrypto/BigInt/SignedBigInteger.h>
 #include <LibJS/Runtime/Completion.h>
+#include <LibJS/Runtime/Date.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/Instant.h>

Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.cpp

@@ -54,14 +54,6 @@ String canonicalize_time_zone_name(String const& time_zone)
     return *iana_time_zone;
 }
 
-// 11.1.3 DefaultTimeZone ( ), https://tc39.es/proposal-temporal/#sec-defaulttimezone
-// 15.1.3 DefaultTimeZone ( ), https://tc39.es/proposal-temporal/#sup-defaulttimezone
-String default_time_zone()
-{
-    // The DefaultTimeZone abstract operation returns a String value representing the valid (11.1.1) and canonicalized (11.1.2) time zone name for the host environment's current time zone.
-    return ::TimeZone::current_time_zone();
-}
-
 // 11.6.1 CreateTemporalTimeZone ( identifier [ , newTarget ] ), https://tc39.es/proposal-temporal/#sec-temporal-createtemporaltimezone
 ThrowCompletionOr<TimeZone*> create_temporal_time_zone(VM& vm, String const& identifier, FunctionObject const* new_target)
 {

Userland/Libraries/LibJS/Runtime/Temporal/TimeZone.h

@@ -38,7 +38,6 @@ private:
 
 bool is_valid_time_zone_name(String const& time_zone);
 String canonicalize_time_zone_name(String const& time_zone);
-String default_time_zone();
 ThrowCompletionOr<TimeZone*> create_temporal_time_zone(VM&, String const& identifier, FunctionObject const* new_target = nullptr);
 ISODateTime get_iso_parts_from_epoch(VM&, Crypto::SignedBigInteger const& epoch_nanoseconds);
 BigInt* get_iana_time_zone_next_transition(VM&, BigInt const& epoch_nanoseconds, StringView time_zone_identifier);