Cleanup of GiST extensions in contrib/: now that we always invoke GiST

methods in a short-lived memory context, there is no need for GiST methods
to do their own manual (and error-prone) memory management.

contrib/btree_gist/btree_utils_num.c

@@ -246,7 +246,5 @@ gbt_num_picksplit(const GistEntryVector *entryvec, GIST_SPLITVEC *v,
 		}
 	}
 
-	pfree(arr);
-
 	return v;
 }