pgsql: Pass down information on table modification to scan nodes

Pass down information on table modification to scan nodes

Pass down information to sequential scan, index [only] scan, bitmap
table scan, sample scan, and TID range scan nodes on whether or not the
query modifies the relation being scanned. A later commit will use this
information to update the VM during on-access pruning only if the
relation is not modified by the query.

Author: Melanie Plageman <melanieplageman(at)gmail(dot)com>
Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Reviewed-by: Andrey Borodin <x4mmm(at)yandex-team(dot)ru>
Reviewed-by: Tomas Vondra <tomas(at)vondra(dot)me>
Reviewed-by: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Discussion: https://postgr.es/m/4379FDA3-9446-4E2C-9C15-32EFE8D4F31B%40yandex-team.ru

Branch
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master

Details
-------
https://git.postgresql.org/pg/commitdiff/50eb5faea2959125a575bae0a062ccb33b49c43d

Modified Files
--------------
src/backend/executor/execUtils.c | 21 +++++++++++++++++++++
src/backend/executor/nodeBitmapHeapscan.c | 3 ++-
src/backend/executor/nodeIndexonlyscan.c | 9 ++++++---
src/backend/executor/nodeIndexscan.c | 12 ++++++++----
src/backend/executor/nodeSamplescan.c | 3 ++-
src/backend/executor/nodeSeqscan.c | 10 +++++++---
src/backend/executor/nodeTidrangescan.c | 11 ++++++++---
src/include/access/tableam.h | 3 +++
src/include/executor/executor.h | 2 ++
9 files changed, 59 insertions(+), 15 deletions(-)