reduce par_len in custom mpsc+spsc STM tests

Author: jmid

test/mpsc_queue/stm_mpsc_queue.ml

@@ -123,7 +123,7 @@ let agree_prop_par (seq_pref, consumer, producer) =
    "Consumer domain" cmds can't be [Push] (but can be [Pop], [Is_empty], [Close] or [Push_head]),
    "producer domain" cmds can't be [Push_head] or [Pop] (but can be [Push], [Is_empty] or [Close]). *)
 let arb_cmds_par =
-  WSDT_dom.arb_triple 20 15 WSDConf.arb_cmd WSDConf.arb_cmd WSDConf.producer_cmd
+  WSDT_dom.arb_triple 20 12 WSDConf.arb_cmd WSDConf.arb_cmd WSDConf.producer_cmd
 
 (* A parallel agreement test - w/repeat and retries combined *)
 let agree_test_par ~count ~name =

test/spsc_queue/stm_spsc_queue.ml

@@ -97,7 +97,7 @@ let agree_prop_par (seq_pref, producer, consumer) =
 (* [arb_cmds_par] differs in what each triple component generates:
    "Producer domain" cmds can't be [Pop], "consumer domain" cmds can only be [Pop]. *)
 let arb_cmds_par =
-  WSDT_dom.arb_triple 20 15 WSDConf.producer_cmd WSDConf.producer_cmd
+  WSDT_dom.arb_triple 20 12 WSDConf.producer_cmd WSDConf.producer_cmd
     WSDConf.consumer_cmd
 
 (* A parallel agreement test - w/repeat and retries combined *)