events: optimize listener array cloning
This both switches to a single algorithm for array cloning and also
speeds up (by ~100% in the ee-listeners-many benchmark) the
"many elements" case that was previously handled by
array.slice().
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This both switches to a single algorithm for array cloning and also
speeds up (by ~100% in the ee-listeners-many benchmark) the
"many elements" case that was previously handled by
array.slice().