Remove add_table test because it's very slow and tends to fail

https://github.com/2ndQuadrant/pglogical/issues/126

--- a/Makefile
+++ b/Makefile
@@ -41,7 +41,7 @@ OBJS = pglogical_apply.o pglogical_confl
 SCRIPTS_built = pglogical_create_subscriber
 
 REGRESS = preseed infofuncs init_fail init preseed_check basic extended conflict_secondary_unique \
-		  toasted replication_set add_table matview bidirectional primary_key \
+		  toasted replication_set matview bidirectional primary_key \
 		  interfaces foreign_key functions copy triggers parallel row_filter \
 		  row_filter_sampling att_list column_filter apply_delay multiple_upstreams \
 		  node_origin_cascade drop
