Fixed #21074 -- Added tests for localized datetime fields.

Fields must render values in the current time zone.

This commit only contains tests because this ticket was just a symptom of
a regression from #18777 that was fixed separately.

tests/timezones/forms.py

@@ -8,7 +8,16 @@ class EventForm(forms.Form):
 class EventSplitForm(forms.Form):
     dt = forms.SplitDateTimeField()
 
+class EventLocalizedForm(forms.Form):
+    dt = forms.DateTimeField(localize=True)
+
 class EventModelForm(forms.ModelForm):
     class Meta:
         model = Event
         fields = '__all__'
+
+class EventLocalizedModelForm(forms.ModelForm):
+    class Meta:
+        model = Event
+        fields = '__all__'
+        localized_fields = '__all__'