pgsql: Don't throw an error for LOCK TABLE on a self-referential view.

Don't throw an error for LOCK TABLE on a self-referential view.

LOCK TABLE has complained about "infinite recursion" when applied
to a self-referential view, ever since we made it recurse into views
in v11. However, that breaks pg_dump's new assumption that it's
okay to lock every relation. There doesn't seem to be any good
reason to throw an error: if we just abandon the recursion, we've
still satisfied the requirement of locking every referenced relation.

Per bug #16703 from Andrew Bille (via Alexander Lakhin).

Discussion: https://postgr.es/m/16703-e348f58aab3cf6cc@postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/5b7bfc39726ff9f6c52dd73e337c34e74e0d1f39

Modified Files
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src/backend/commands/lockcmds.c | 21 ++++++++++++---------
src/test/regress/expected/lock.out | 4 +---
src/test/regress/sql/lock.sql | 2 +-
3 files changed, 14 insertions(+), 13 deletions(-)