pgsql: Replace calls to pg_qsort() with the qsort() macro.

Replace calls to pg_qsort() with the qsort() macro.

Calls to this function might give the impression that pg_qsort()
is somehow different than qsort(), when in fact there is a qsort()
macro in port.h that expands all in-tree uses to pg_qsort().

Reviewed-by: Mats Kindahl
Discussion: https://postgr.es/m/CA%2B14426g2Wa9QuUpmakwPxXFWG_1FaY0AsApkvcTBy-YfS6uaw%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/5497daf3aa2ae6ec9d5097f25c40627f8c801de8

Modified Files
--------------
contrib/pg_prewarm/autoprewarm.c            |  4 ++--
src/backend/access/brin/brin_minmax_multi.c |  2 +-
src/backend/optimizer/plan/analyzejoins.c   |  4 ++--
src/backend/storage/buffer/bufmgr.c         |  4 ++--
src/backend/utils/cache/syscache.c          | 10 +++++-----
src/include/port.h                          |  4 ++++
6 files changed, 16 insertions(+), 12 deletions(-)