To enable or disable the GUC gp_enable_global_deadlock_detector,
restart is required. But this GUC is only used on master, so just
restart master instead of full cluster. This helps to cut-down the
test time by a min. Also, in process remove the pg_sleep(2) calls, as
GUCs gp_enable_global_deadlock_detector and
gp_global_deadlock_detector_period can be set sametime and hence don't
need separate time to reload the config and waste time.

Also, removing prepare-for-local as only one test exists for local
locks which is local-deadlock-03, hence directly prepare for the same
inside that sql file.