pgsql: Align tests for stored and virtual generated columns

Align tests for stored and virtual generated columns

These tests were intended to be aligned with each other, but
additional tests for virtual generated columns disrupted that
alignment.  The test confirming that user-defined types are not
allowed in virtual generated columns has also been moved to the
generated_virtual.sql-specific section.

Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Paul A Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Mutaamba Maasha <maasha@gmail.com>
Reviewed-by: Surya Poondla <s_poondla@apple.com>
Discussion: https://www.postgresql.org/message-id/flat/20250808115142.e9ccb81f35466a9a131a4c55@sraoss.co.jp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/9a9998163bda0d8c17d84ea22ced6a60f8018634

Modified Files
--------------
src/test/regress/expected/generated_stored.out  | 70 ++++++++++++++++++++++++-
src/test/regress/expected/generated_virtual.out | 14 ++---
src/test/regress/sql/generated_stored.sql       | 51 +++++++++++++++++-
src/test/regress/sql/generated_virtual.sql      |  8 +--
4 files changed, 128 insertions(+), 15 deletions(-)