pgsql: Fix heap_page_prune() parameter order confusion introduced in dc

Fix heap_page_prune() parameter order confusion introduced in dc7420c2c92.

Both luckily and unluckily the passed values meant the same for all
types. Luckily because that meant my confusion caused no harm,
unluckily because otherwise the compiler might have warned...

In passing, synchronize parameter names between definition and
declaration.

Reported-By: Peter Geoghegan <pg@bowt.ie>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAH2-Wz=L=nBoepQdH9b5Qd0nMvepFT2CnT6sjWvvpOXa=K8HVQ@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/8001cb77ee6cb4f32632850d41f00206a86bac3e

Modified Files
--------------
src/backend/access/heap/vacuumlazy.c | 4 ++--
src/include/access/heapam.h          | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)