pgsql: Remove PointerIsValid()

Remove PointerIsValid()

This doesn't provide any value over the standard style of checking the
pointer directly or comparing against NULL.

Also remove related:
- AllocPointerIsValid() [unused]
- IndexScanIsValid() [had one user]
- HeapScanIsValid() [unused]
- InvalidRelation [unused]

Leaving HeapTupleIsValid(), ItemIdIsValid(), PortalIsValid(),
RelationIsValid for now, to reduce code churn.

Reviewed-by: Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/ad50ab6b-6f74-4603-b099-1cd6382fb13d%40eisentraut.org
Discussion: https://www.postgresql.org/message-id/CA+hUKG+NFKnr=K4oybwDvT35dW=VAjAAfiuLxp+5JeZSOV3nBg@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/bccf2803-5252-47c2-9ff0-340502d5bd1c@iki.fi

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/a5b35fcedb542587e7d8b8fcd21a2e0995b82d2f

Modified Files
--------------
src/backend/access/common/reloptions.c | 8 ++++----
src/backend/access/common/tupdesc.c | 10 +++++-----
src/backend/access/index/indexam.c | 6 +++---
src/backend/access/transam/xact.c | 18 ++++++++---------
src/backend/catalog/index.c | 8 ++++----
src/backend/catalog/objectaddress.c | 2 +-
src/backend/catalog/pg_proc.c | 2 +-
src/backend/catalog/pg_type.c | 2 +-
src/backend/commands/foreigncmds.c | 14 ++++++-------
src/backend/commands/tablecmds.c | 4 ++--
src/backend/nodes/outfuncs.c | 2 +-
src/backend/postmaster/autovacuum.c | 2 +-
src/backend/storage/ipc/sinvaladt.c | 2 +-
src/backend/storage/large_object/inv_api.c | 14 ++++++-------
src/backend/utils/adt/acl.c | 2 +-
src/backend/utils/adt/arrayfuncs.c | 2 +-
src/backend/utils/adt/datum.c | 4 ++--
src/backend/utils/adt/xml.c | 2 +-
src/backend/utils/cache/catcache.c | 2 +-
src/backend/utils/cache/relcache.c | 4 ++--
src/backend/utils/cache/syscache.c | 32 +++++++++++-------------------
src/backend/utils/error/assert.c | 3 +--
src/backend/utils/mmgr/aset.c | 10 ++--------
src/backend/utils/mmgr/bump.c | 2 +-
src/backend/utils/mmgr/generation.c | 4 ++--
src/backend/utils/mmgr/portalmem.c | 18 ++++++++---------
src/backend/utils/mmgr/slab.c | 4 ++--
src/include/access/genam.h | 6 ------
src/include/access/heapam.h | 6 ------
src/include/access/htup.h | 2 +-
src/include/access/itup.h | 2 +-
src/include/c.h | 6 ------
src/include/lib/radixtree.h | 2 +-
src/include/storage/itemid.h | 2 +-
src/include/storage/itemptr.h | 14 ++++++-------
src/include/utils/portal.h | 2 +-
src/include/utils/rel.h | 4 +---
37 files changed, 97 insertions(+), 132 deletions(-)