pgsql: Add 'static' to file-local variables missing it.

Add 'static' to file-local variables missing it.

Noticed when comparing the set of exported symbols without / with
-fvisibility=hidden after adding PGDLLIMPORT to intentionally exported
symbols.

Discussion: https://postgr.es/m/20220512164513.vaheofqp2q24l65r@alap3.anarazel.de

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/09cd33f47bb32f904c32b5aabe607a5125159cc4

Modified Files
--------------
src/backend/access/common/reloptions.c      | 6 +++---
src/backend/access/transam/commit_ts.c      | 2 +-
src/backend/access/transam/xact.c           | 6 +++---
src/backend/catalog/storage.c               | 2 +-
src/backend/replication/logical/launcher.c  | 2 +-
src/backend/replication/logical/tablesync.c | 2 +-
src/backend/replication/logical/worker.c    | 2 +-
src/backend/tcop/cmdtag.c                   | 2 +-
8 files changed, 12 insertions(+), 12 deletions(-)