Обсуждение: pgsql: Fix incorrect computations of length of null bitmap inpageinspe

Fix incorrect computations of length of null bitmap in pageinspect.

Instead of using our standard macro for this calculation, this code
did it itself ... and got it wrong, leading to incorrect display of
the null bitmap in some cases.  Noted and fixed by Maksim Milyutin.

In passing, remove a uselessly duplicative error check.

Errors were introduced in commit d6061f83a; back-patch to 9.6
where that came in.

Maksim Milyutin, reviewed by Andrey Borodin

Discussion: https://postgr.es/m/ec295792-a69f-350f-6287-25a20e8f31d5@gmail.com

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/5ad1b1728767dbf0209b35072db372d19bc032f7

Modified Files
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contrib/pageinspect/expected/page.out | 17 +++++++++++++++++
contrib/pageinspect/heapfuncs.c       | 15 +++++----------
contrib/pageinspect/sql/page.sql      |  8 ++++++++
3 files changed, 30 insertions(+), 10 deletions(-)