Fixed #11313 -- Made ModelAdmin.list_editable more resilient to concurrent edits.

Allowed admin POSTed bulk-edit data to use modeladmin.get_queryset()
so that the ids in the POST data have a chance to match up even if
the objects on the current page changed based on the ordering.

tests/admin_changelist/admin.py

@@ -111,6 +111,8 @@ site.register(Parent, NoListDisplayLinksParentAdmin)
 class SwallowAdmin(admin.ModelAdmin):
     actions = None  # prevent ['action_checkbox'] + list(list_display)
     list_display = ('origin', 'load', 'speed', 'swallowonetoone')
+    list_editable = ['load', 'speed']
+    list_per_page = 3
 
 site.register(Swallow, SwallowAdmin)