pgsql: Remove postmaster.c's reset_shared() wrapper function.

Remove postmaster.c's reset_shared() wrapper function.

reset_shared just invokes CreateSharedMemoryAndSemaphores, so let's
get rid of it and invoke that directly.  This removes a confusing
seeming-inconsistency between the postmaster's startup sequence
and the startup sequence used in standalone mode.

Nathan Bossart, reviewed by Pavel Borisov

Discussion: https://postgr.es/m/20220329221702.GA559657@nathanxps13

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/5e692dcacabd5dbc8ccfb9e37a2d26a574b6dea6

Modified Files
--------------
src/backend/postmaster/postmaster.c | 27 +++++++--------------------
1 file changed, 7 insertions(+), 20 deletions(-)