pgsql: Update expected output for contrib/sepgsql's regression tests.

Update expected output for contrib/sepgsql's regression tests.

Commit 65281391a caused some additional error context lines to
appear in the output of one test case. That's fine, but we missed
updating the expected output. Do it now.

While here, add some missing test-output subdirectories to
contrib/sepgsql/.gitignore, so that we don't get git warnings
after running the tests.

Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Discussion: https://postgr.es/m/1613232.1761255361@sss.pgh.pa.us
Backpatch-through: 18

Branch
------
REL_18_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/67ef5575ccb07d2dd5322aef33e01b3c2a4b9047

Modified Files
--------------
contrib/sepgsql/.gitignore | 4 +++-
contrib/sepgsql/expected/ddl.out | 6 ++++++
2 files changed, 9 insertions(+), 1 deletion(-)