pgsql: Invalidate relcache for publications defined for all tables.

Invalidate relcache for publications defined for all tables.

Updates/Deletes on a relation were allowed even without replica identity
after we define the publication for all tables. This would later lead to
an error on subscribers. The reason was that for such publications we were
not invalidating the relcache and the publication information for
relations was not getting rebuilt. Similarly, we were not invalidating the
relcache after dropping of such publications which will prohibit
Updates/Deletes without replica identity even without any publication.

Author: Vignesh C and Hou Zhijie
Reviewed-by: Hou Zhijie, Kyotaro Horiguchi, Amit Kapila
Backpatch-through: 10, where it was introduced
Discussion: https://postgr.es/m/CALDaNm0pF6zeWqCA8TCe2sDuwFAy8fCqba=nHampCKag-qLixg@mail.gmail.com

Branch
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REL_13_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ddfc7299d0a3a41f0c178a8157bd751430428e8a

Modified Files
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src/backend/commands/publicationcmds.c    | 14 +++++++++++++-
src/test/regress/expected/publication.out | 15 +++++++++++++++
src/test/regress/sql/publication.sql      | 14 ++++++++++++++
3 files changed, 42 insertions(+), 1 deletion(-)