pgsql: Remove ATT_TABLE for ALTER TABLE ... ATTACH/DETACH

Remove ATT_TABLE for ALTER TABLE ... ATTACH/DETACH

Attempting these commands for a non-partitioned table would result in a
failure when creating the relation in transformPartitionCmd(). This
gives the possibility to throw an error earlier with a much better error
message, thanks to d69a3f4d70b7.

The extra test cases are from me. Note that FINALIZE uses a different
subcommand and it had no coverage for its failure path with
non-partitioned tables.

Author: Álvaro Herrera, Michael Paquier
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/202409190803.tnis52adt2n5@alvherre.pgsql

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bbba59e69a56e1622e270f5e47b402c3a904cefc

Modified Files
--------------
src/backend/commands/tablecmds.c | 8 +++-----
src/test/regress/expected/alter_table.out | 12 ++++++++++--
src/test/regress/sql/alter_table.sql | 2 ++
3 files changed, 15 insertions(+), 7 deletions(-)