pgsql: Use the new castNode() macro in a number of places.

Use the new castNode() macro in a number of places.

This is far from a pervasive conversion, but it's a good starting
point.

Author: Peter Eisentraut, with some minor changes by me
Reviewed-By: Tom Lane
Discussion: https://postgr.es/m/c5d387d9-3440-f5e0-f9d4-71d53b9fbe52@2ndquadrant.com

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/9ba8a9ce4548bb34b7136b7463a61b2c499979a3

Modified Files
--------------
contrib/pg_stat_statements/pg_stat_statements.c | 10 ++++------
contrib/postgres_fdw/deparse.c | 5 +----
contrib/postgres_fdw/postgres_fdw.c | 12 ++++--------
src/backend/catalog/pg_proc.c | 3 +--
src/backend/commands/aggregatecmds.c | 4 ++--
src/backend/commands/analyze.c | 6 +++---
src/backend/commands/async.c | 8 ++++----
src/backend/commands/collationcmds.c | 2 +-
src/backend/commands/constraint.c | 2 +-
src/backend/commands/copy.c | 12 ++++++------
src/backend/commands/createas.c | 5 ++---
src/backend/commands/dropcmds.c | 4 +---
src/backend/commands/explain.c | 16 +++++++---------
src/backend/commands/functioncmds.c | 7 ++-----
src/backend/commands/matview.c | 3 +--
src/backend/commands/opclasscmds.c | 9 +++------
src/backend/commands/tablecmds.c | 16 +++++-----------
src/backend/commands/trigger.c | 4 +---
src/backend/commands/user.c | 4 +---
src/backend/commands/view.c | 3 +--
src/backend/executor/execAmi.c | 7 ++++---
src/backend/executor/execQual.c | 6 ++----
src/backend/executor/execTuples.c | 5 +----
src/backend/executor/functions.c | 6 ++----
src/backend/executor/nodeAgg.c | 8 +++-----
src/backend/executor/nodeCtescan.c | 3 +--
src/backend/executor/nodeCustom.c | 4 ++--
src/backend/executor/nodeHashjoin.c | 7 ++-----
src/backend/executor/nodeLockRows.c | 4 +---
src/backend/executor/nodeModifyTable.c | 4 +---
src/backend/executor/nodeSubplan.c | 15 +++++----------
src/backend/executor/nodeWorktablescan.c | 4 ++--
32 files changed, 77 insertions(+), 131 deletions(-)