Refactor heap_page_prune_and_freeze() parameters into a struct

heap_page_prune_and_freeze() had accumulated an unwieldy number of input
parameters and upcoming work to handle VM updates in this function will
add even more.

Introduce a new PruneFreezeParams struct to group the function’s input
parameters, improving readability and maintainability.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Discussion: https://postgr.es/m/yn4zp35kkdsjx6wf47zcfmxgexxt4h2og47pvnw2x5ifyrs3qc%407uw6jyyxuyf7