Remove bogus Assert in make_partitionedrel_pruneinfo().

This Assert thought that a given rel couldn't be both leaf and
non-leaf, but it turns out that in some unusual plan trees
that's wrong, so remove it.

The lack of testing for cases like that is quite concerning ---
there is little reason for confidence that there aren't other
bugs in the area.  But developing a stable test case seems
rather difficult, and in any case we don't need this Assert.

David Rowley

Discussion: https://postgr.es/m/CAJGNTeOkdk=UVuMugmKL7M=owgt4nNr1wjxMg1F+mHsXyLCzFA@mail.gmail.com

src/backend/partitioning/partprune.c

@@ -347,8 +347,6 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
 		Assert(rti < root->simple_rel_array_size);
 		/* No duplicates please */
 		Assert(relid_subpart_map[rti] == 0);
-		/* Same rel cannot be both leaf and non-leaf */
-		Assert(relid_subplan_map[rti] == 0);
 
 		relid_subpart_map[rti] = i++;
 	}