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@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1613232.1761255361@sss.pgh.pa.us
Backpatch-through: 18