pgsql: Always call ExecShutdownNode() if appropriate.

Always call ExecShutdownNode() if appropriate.

Call ExecShutdownNode() after ExecutePlan()'s loop, rather than at each
break.  We had forgotten to do that in one case.  The omission caused
intermittent "temporary file leak" warnings from multi-batch parallel
hash joins with a LIMIT clause.

Back-patch to 11.  Though the problem exists in theory in earlier
parallel query releases, nothing really depended on it.

Author: Kyotaro Horiguchi
Reviewed-by: Thomas Munro, Amit Kapila
Discussion: https://postgr.es/m/20191111.212418.2222262873417235945.horikyota.ntt%40gmail.com

Branch
------
REL_12_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/24897e1a1af27dc759fb41afba2a663ff9af4ef6

Modified Files
--------------
src/backend/executor/execMain.c | 23 +++++++----------------
1 file changed, 7 insertions(+), 16 deletions(-)