Pref Regressions for "Use `NonNull` in `UnsafeWorldCell` (#25632)"

[hymm]

Bevy version

• a716a99

Regressions in Bevy Metrics

https://metrics.bevy.org/benchmarks_z.html#1559ad0ea5bf36ed569d853f07a59fca1b8dd8bd

Sees regressions:

• query_get_many_*
• get_entity_mut_slice_*
• ecs_resources_insert_remove
• despawn_world_recursive*
• event_propagation_four_event_types

Sees improvements:

• world_entity_50000_entities
• observe_observer_custom*

I manually checked some of these as the metrics change encompasses multiple prs.

• query_get_many: I actually see an improvement of 20%. Might be a difference between windows and linux.
• get_entity_mut_slice: I can confirm the 20% regression here.
• observe_observer_custom: I can confirm a 5% improvement.

I'm not 100% sure if we should revert or not, since there's both improments and regressions. We should probably look at the assembly and see if we can understand what is going on better.