Make an API to help with the pattern of 'replaces the values of the REE array'

[alamb]

this pattern of 'replaces the values of the REE array' is probably common enough to warrant its own function on RunArray eventually. Maybe some thing like

let out_ree = ree.with_new_values(inner_value_lengths)

And then internally it can update the data type and that the number of inner values is correct 🤔

Originally posted by @alamb in #9838 (comment)

[alamb]

If we make this PR we should update the existing callsites in the code to use it (e.g. the one in #9838) as a way to show we have an API that can be used

[Rich-T-kid]

take