pgsql: Fix assertion in pg_get_shmem_pagesize() in single-user mode

Fix assertion in pg_get_shmem_pagesize() in single-user mode

Remove assertion that was too strict, and tripped if you queried the
pg_shmem_allocations_numa or the pg_buffercache_os_pages view in
single-user mode.

The point of the assertion was that the function should only be called
after "the server has started", but it would be OK to call it from the
postmaster, too, as long as it's after startup, specifically after
huge_pages_status has been set. We already have a direct assertion
for that.

Author: Ayush Tiwari <ayushtiwari(dot)slg01(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/CAJTYsWV-=w5_oFgCnfAixWGc=gMa2pkDinLyGLsb4sKcDaf2FA@mail.gmail.com
Backpatch-through: 18

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/89829354de1b5f3f8cb3dbdd2f2fc087f981a1b3

Modified Files
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src/backend/storage/ipc/shmem.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)