pgsql: Add regression tests for VACUUM and ANALYZE with relation skips

Add regression tests for VACUUM and ANALYZE with relation skips

When a user does not have ownership on a relation, then specific log
messages are generated.  This new test suite adds coverage for all the
possible log messages generated, which will be useful to check the
consistency of any refactoring related to ownership checks for relations
vacuumed or analyzed.

Author: Michael Paquier
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/20180812222142.GA6097@paquier.xyz

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/98abc738027e866f89b0ecf6f6a30b16e000e804

Modified Files
--------------
src/test/regress/expected/vacuum.out | 28 ++++++++++++++++++++++++++++
src/test/regress/sql/vacuum.sql      | 20 ++++++++++++++++++++
2 files changed, 48 insertions(+)