pgsql: Remove preprocessor guards from injection points

Remove preprocessor guards from injection points

When defining an injection point there is no need to wrap the definition
with USE_INJECTION_POINT guards, the INJECTION_POINT macro is available
in all builds. Remove to make the code consistent.

Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: /messages/by-id/OSCPR01MB14966C8015DEB05ABEF2CE077F51FA@OSCPR01MB14966.jpnprd01.prod.outlook.com
Backpatch-through: 17

Branch
------
REL_18_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/efc26d17a7d40e58fa60f7f39dac892eb7f82cbb

Modified Files
--------------
src/backend/access/transam/xlog.c | 2 --
1 file changed, 2 deletions(-)