Add some tests for CREATE OR REPLACE VIEW with column additions

When working on an already-defined view with matching attributes, CREATE
OR REPLACE VIEW would internally generate an ALTER TABLE command with a
set of AT_AddColumnToView sub-commands, one for each attribute added.

Such a command is stored in event triggers twice:
- Once as a simple command.
- Once as an ALTER TABLE command, as it has sub-commands.

There was no test coverage to track this command pattern in terms of
event triggers and DDL deparsing:
- For the test module test_ddl_deparse, two command notices are issued.
- For event triggers, a CREATE VIEW command is logged twice, which may
look a bit weird first, but again this maps with the internal behavior
of how the commands are built, and how the event trigger code reacts in
terms of commands gathered.

While on it, this adds a test for CREATE SCHEMA with a CREATE VIEW
command embedded in it, case supported by the grammar but not covered
yet.

This hole in the test coverage has been found while digging into what
would be a similar behavior for sequences if adding attributes to them
with ALTER TABLE variants, after the initial relation creation.

Discussion: https://postgr.es/m/aaFG9bqkEn0RhLJG@paquier.xyz

src/test/modules/test_ddl_deparse/expected/create_view.out

@@ -12,6 +12,12 @@ NOTICE:    subcommand: type REPLACE RELOPTIONS desc <NULL>
 CREATE VIEW datatype_view AS
   SELECT * FROM datatype_table;
 NOTICE:  DDL test: type simple, tag CREATE VIEW
+CREATE OR REPLACE VIEW datatype_view AS
+  SELECT * FROM datatype_table, static_view;
+NOTICE:  DDL test: type simple, tag CREATE VIEW
+NOTICE:  DDL test: type alter table, tag CREATE VIEW
+NOTICE:    subcommand: type ADD COLUMN TO VIEW desc column col of view datatype_view
+NOTICE:    subcommand: type REPLACE RELOPTIONS desc <NULL>
 CREATE RECURSIVE VIEW nums_1_100 (n) AS
     VALUES (1)
 UNION ALL

src/test/modules/test_ddl_deparse/sql/create_view.sql

@@ -11,6 +11,9 @@ CREATE OR REPLACE VIEW static_view AS
 CREATE VIEW datatype_view AS
   SELECT * FROM datatype_table;
 
+CREATE OR REPLACE VIEW datatype_view AS
+  SELECT * FROM datatype_table, static_view;
+
 CREATE RECURSIVE VIEW nums_1_100 (n) AS
     VALUES (1)
 UNION ALL

src/test/regress/expected/event_trigger.out

@@ -416,7 +416,8 @@ CREATE SCHEMA evttrig
 	CREATE TABLE one (col_a SERIAL PRIMARY KEY, col_b text DEFAULT 'forty two', col_c SERIAL)
 	CREATE INDEX one_idx ON one (col_b)
 	CREATE TABLE two (col_c INTEGER CHECK (col_c > 0) REFERENCES one DEFAULT 42)
-	CREATE TABLE id (col_d int NOT NULL GENERATED ALWAYS AS IDENTITY);
+	CREATE TABLE id (col_d int NOT NULL GENERATED ALWAYS AS IDENTITY)
+	CREATE VIEW one_view AS SELECT * FROM two;
 NOTICE:  END: command_tag=CREATE SCHEMA type=schema identity=evttrig
 NOTICE:  END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.one_col_a_seq
 NOTICE:  END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.one_col_c_seq
@@ -429,7 +430,14 @@ NOTICE:  END: command_tag=ALTER TABLE type=table identity=evttrig.two
 NOTICE:  END: command_tag=CREATE SEQUENCE type=sequence identity=evttrig.id_col_d_seq
 NOTICE:  END: command_tag=CREATE TABLE type=table identity=evttrig.id
 NOTICE:  END: command_tag=ALTER SEQUENCE type=sequence identity=evttrig.id_col_d_seq
+NOTICE:  END: command_tag=CREATE VIEW type=view identity=evttrig.one_view
 NOTICE:  END: command_tag=CREATE INDEX type=index identity=evttrig.one_idx
+-- View with column additions
+CREATE OR REPLACE VIEW evttrig.one_view AS SELECT * FROM evttrig.two, evttrig.id;
+NOTICE:  END: command_tag=CREATE VIEW type=view identity=evttrig.one_view
+NOTICE:  END: command_tag=CREATE VIEW type=view identity=evttrig.one_view
+DROP VIEW evttrig.one_view;
+NOTICE:  NORMAL: orig=t normal=f istemp=f type=view identity=evttrig.one_view schema=evttrig name=one_view addr={evttrig,one_view} args={}
 -- Partitioned tables with a partitioned index
 CREATE TABLE evttrig.parted (
     id int PRIMARY KEY)

src/test/regress/sql/event_trigger.sql

@@ -324,7 +324,12 @@ CREATE SCHEMA evttrig
 	CREATE TABLE one (col_a SERIAL PRIMARY KEY, col_b text DEFAULT 'forty two', col_c SERIAL)
 	CREATE INDEX one_idx ON one (col_b)
 	CREATE TABLE two (col_c INTEGER CHECK (col_c > 0) REFERENCES one DEFAULT 42)
-	CREATE TABLE id (col_d int NOT NULL GENERATED ALWAYS AS IDENTITY);
+	CREATE TABLE id (col_d int NOT NULL GENERATED ALWAYS AS IDENTITY)
+	CREATE VIEW one_view AS SELECT * FROM two;
+
+-- View with column additions
+CREATE OR REPLACE VIEW evttrig.one_view AS SELECT * FROM evttrig.two, evttrig.id;
+DROP VIEW evttrig.one_view;
 
 -- Partitioned tables with a partitioned index
 CREATE TABLE evttrig.parted (