pgsql: Use more consistently int64 for page numbers in SLRU-related cod

Use more consistently int64 for page numbers in SLRU-related code

clog.c, async.c and predicate.c included some SLRU page numbers still
handled as 4-byte integers, while int64 should be used for this purpose.

These holes have been introduced in 4ed8f0913bfd, that has introduced
the use of 8-byte integers for SLRU page numbers, still forgot about the
code paths updated by this commit.

Reported-by: Noah Misch
Author: Aleksander Alekseev, Michael Paquier
Discussion: https://postgr.es/m/20240626002747.dc.nmisch@google.com
Backpatch-through: 17

Branch
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REL_17_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/165ea79a60774a0e287bfc5dc07363194c6d58df

Modified Files
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src/backend/access/transam/clog.c | 4 ++--
src/backend/commands/async.c | 22 +++++++++++-----------
src/backend/storage/lmgr/predicate.c | 6 +++---
3 files changed, 16 insertions(+), 16 deletions(-)