pgsql: Remove unused check in heap_xlog_insert()

Remove unused check in heap_xlog_insert()

8e03eb92e9a reverted the commit 39b66a91bd which allowed freezing
in the heap_insert() code path but forgot to remove the corresponding
check in heap_xlog_insert(). This code is extraneous but not harmful.
However, cleaning it up makes it very clear that, as of now, we do not
support any freezing of pages in the heap_insert() path.

Author: Melanie Plageman <melanieplageman(at)gmail(dot)com>
Reviewed-by: Tomas Vondra <tomas(at)vondra(dot)me>
Discussion: https://postgr.es/m/flat/CAAKRu_Zp4Pi-t51OFWm1YZ-cctDfBhHCMZ%3DEx6PKxv0o8y2GvA%40mail.gmail.com
Backpatch-through: 14

Branch
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REL_14_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/5a24c20c8442168fd75ff878eb6f99026a31b58b

Modified Files
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src/backend/access/heap/heapam.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)