pgsql: postmaster: Adjust which processes we expect to have exited

postmaster: Adjust which processes we expect to have exited

Comments and code stated that we expect checkpointer to have been signalled in
case of immediate shutdown / fatal errors, but didn't treat archiver and
walsenders the same. That doesn't seem right.

I had started digging through the history to see where this oddity was
introduced, but it's not the fault of a single commit.

Instead treat archiver, checkpointer, and walsenders the same.

Reviewed-by: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
Discussion: https://postgr.es/m/kgng5nrvnlv335evmsuvpnh354rw7qyazl73kdysev2cr2v5zu@m3cfzxicm5kp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f15538cd27d4eeb7d665263a3d7b5700362d7eb0

Modified Files
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src/backend/postmaster/postmaster.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)