pgsql: heapam: Move logic to handle HEAP_MOVED into a helper function

heapam: Move logic to handle HEAP_MOVED into a helper function

Before we dealt with this in 6 near identical and one very similar copy.

The helper function errors out when encountering a
HEAP_MOVED_IN/HEAP_MOVED_OUT tuple with xvac considered current or
in-progress. It'd be preferrable to do that change separately, but otherwise
it'd not be possible to deduplicate the handling in
HeapTupleSatisfiesVacuum().

Reviewed-by: Heikki Linnakangas <hlinnaka(at)iki(dot)fi>
Discussion: https://postgr.es/m/lxzj26ga6ippdeunz6kuncectr5gfuugmm2ry22qu6hcx6oid6@lzx3sjsqhmt6
Discussion: https://postgr.es/m/6rgb2nvhyvnszz4ul3wfzlf5rheb2kkwrglthnna7qhe24onwr@vw27225tkyar

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/548de59d93d5593d5ef5354241510d57b68959db

Modified Files
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src/backend/access/heap/heapam_visibility.c | 293 ++++++----------------------
1 file changed, 61 insertions(+), 232 deletions(-)