Re-assess Points of No Return

[dyceron]

There are inconsistencies regarding certain Point of No Returns. Ideally, we should be consistent and decide what to change. Some item rooms have been changed so they can be open checks, while others were left. For the sake of consistency, we should change all of them or none of them. I'm leaning more towards changing them all back.

There are other PONRs that exist, like one-way doors for Metroids, certain paths, but these are probably fine to keep.