pgsql: Remove redundant IndexTupleDSize macro.

Remove redundant IndexTupleDSize macro.

Use IndexTupleSize everywhere, instead. Also, remove IndexTupleSize's
internal typecast, as that's not really needed and might mask coding
errors. Change some pointer variable datatypes in the call sites
to compensate for that and make it clearer what we're assuming.

Ildar Musin, Robert Haas, Stephen Frost

Discussion: https://postgr.es/m/0274288e-9e88-13b6-c61c-7b36928bf221@postgrespro.ru

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d79e7e92bf2a44415e1dcbd74274eb79852fc885

Modified Files
--------------
src/backend/access/hash/hash_xlog.c | 4 ++--
src/backend/access/hash/hashinsert.c | 6 +++---
src/backend/access/hash/hashovfl.c | 2 +-
src/backend/access/hash/hashpage.c | 2 +-
src/backend/access/heap/hio.c | 4 ++--
src/backend/access/nbtree/nbtinsert.c | 6 +++---
src/backend/access/nbtree/nbtsort.c | 2 +-
src/backend/access/nbtree/nbtxlog.c | 32 +++++++++++++++++++-------------
src/include/access/itup.h | 3 +--
9 files changed, 33 insertions(+), 28 deletions(-)