pgsql: Remove INSERT privilege check at table creation of CTAS and matv

Remove INSERT privilege check at table creation of CTAS and matview

As per discussion with Peter Eisentraunt, the SQL standard specifies
that any tuple insertion done as part of CREATE TABLE AS happens without
any extra ACL check, so it makes little sense to keep a check for INSERT
privileges when using WITH DATA.  Materialized views are not part of the
standard, but similarly, this check can be confusing as this refers to
an access check on a table created within the same command as the one
that would insert data into this table.

This commit removes the INSERT privilege check for WITH DATA, the
default, that 846005e removed partially, but only for WITH NO DATA.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/d049c272-9a47-d783-46b0-46665b011598@enterprisedb.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/878f3a19c6c8ff197e4a33f51d921a4abafcc494

Modified Files
--------------
doc/src/sgml/ref/create_materialized_view.sgml |  3 +-
doc/src/sgml/ref/create_table_as.sgml          |  4 +-
src/backend/commands/createas.c                | 26 --------
src/test/regress/expected/matview.out          | 24 ++++---
src/test/regress/expected/select_into.out      | 86 ++++++++++++--------------
src/test/regress/sql/matview.sql               | 10 +--
src/test/regress/sql/select_into.sql           | 40 ++++--------
7 files changed, 75 insertions(+), 118 deletions(-)